hugetlb.c 117.7 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/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 "internal.h"
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int hugepages_treat_as_movable;
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39
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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/*
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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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	if (spool->min_hpages != -1) {		/* minimum size accounting */
		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;

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	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;

	if (spool->min_hpages != -1) {		/* minimum size accounting */
		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.
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 */
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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;
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		}
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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) {
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		if (!nrg) {
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			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.
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 */
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static long region_del(struct resv_map *resv, long f, long t)
478
{
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	struct list_head *head = &resv->regions;
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	struct file_region *rg, *trg;
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	struct file_region *nrg = NULL;
	long del = 0;
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retry:
485
	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))
495
			continue;
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497
		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.
 */
void hugetlb_fix_reserve_counts(struct inode *inode, bool restore_reserve)
{
	struct hugepage_subpool *spool = subpool_inode(inode);
	long rsv_adjust;

	rsv_adjust = hugepage_subpool_get_pages(spool, 1);
	if (restore_reserve && rsv_adjust) {
		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).
 */
584
static long region_count(struct resv_map *resv, long f, long t)
585
{
586
	struct list_head *head = &resv->regions;
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	struct file_region *rg;
	long chg = 0;

590
	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;
	}
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	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)
617
{
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	return ((address - vma->vm_start) >> huge_page_shift(h)) +
			(vma->vm_pgoff >> huge_page_order(h));
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}

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

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

	if (!is_vm_hugetlb_page(vma))
		return PAGE_SIZE;

	hstate = hstate_vma(vma);

641
	return 1UL << huge_page_shift(hstate);
642
}
643
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
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/*
 * Return the page size being used by the MMU to back a VMA. In the majority
 * of cases, the page size used by the kernel matches the MMU size. On
 * architectures where it differs, an architecture-specific version of this
 * function is required.
 */
#ifndef vma_mmu_pagesize
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
{
	return vma_kernel_pagesize(vma);
}
#endif

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/*
 * Flags for MAP_PRIVATE reservations.  These are stored in the bottom
 * bits of the reservation map pointer, which are always clear due to
 * alignment.
 */
#define HPAGE_RESV_OWNER    (1UL << 0)
#define HPAGE_RESV_UNMAPPED (1UL << 1)
665
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
666

667 668 669 670 671 672 673 674 675
/*
 * 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.
676 677 678 679 680 681 682 683 684
 *
 * 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.
685
 */
686 687 688 689 690 691 692 693 694 695 696
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;
}

697
struct resv_map *resv_map_alloc(void)
698 699
{
	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
700 701 702 703 704
	struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);

	if (!resv_map || !rg) {
		kfree(resv_map);
		kfree(rg);
705
		return NULL;
706
	}
707 708

	kref_init(&resv_map->refs);
709
	spin_lock_init(&resv_map->lock);
710 711
	INIT_LIST_HEAD(&resv_map->regions);

712 713 714 715 716 717
	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;

718 719 720
	return resv_map;
}

721
void resv_map_release(struct kref *ref)
722 723
{
	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
724 725
	struct list_head *head = &resv_map->region_cache;
	struct file_region *rg, *trg;
726 727

	/* Clear out any active regions before we release the map. */
728
	region_del(resv_map, 0, LONG_MAX);
729 730 731 732 733 734 735 736 737

	/* ... 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);

738 739 740
	kfree(resv_map);
}

741 742 743 744 745
static inline struct resv_map *inode_resv_map(struct inode *inode)
{
	return inode->i_mapping->private_data;
}

746
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
747
{
748
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
749 750 751 752 753 754 755
	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 {
756 757
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
758
	}
759 760
}

761
static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
762
{
763 764
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
765

766 767
	set_vma_private_data(vma, (get_vma_private_data(vma) &
				HPAGE_RESV_MASK) | (unsigned long)map);
768 769 770 771
}

static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
{
772 773
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
774 775

	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
776 777 778 779
}

static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
{
780
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
781 782

	return (get_vma_private_data(vma) & flag) != 0;
783 784
}

785
/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
786 787
void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
788
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
789
	if (!(vma->vm_flags & VM_MAYSHARE))
790 791 792 793
		vma->vm_private_data = (void *)0;
}

/* Returns true if the VMA has associated reserve pages */
794
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
795
{
796 797 798 799 800 801 802 803 804 805 806
	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)
807
			return true;
808
		else
809
			return false;
810
	}
811 812

	/* Shared mappings always use reserves */
813 814 815 816 817 818 819 820 821 822 823 824 825
	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;
	}
826 827 828 829 830

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
831
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
832
		return true;
833

834
	return false;
835 836
}

837
static void enqueue_huge_page(struct hstate *h, struct page *page)
L
Linus Torvalds 已提交
838 839
{
	int nid = page_to_nid(page);
840
	list_move(&page->lru, &h->hugepage_freelists[nid]);
841 842
	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
L
Linus Torvalds 已提交
843 844
}

845 846 847 848
static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
{
	struct page *page;

849 850 851 852 853 854 855 856
	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)
857
		return NULL;
858
	list_move(&page->lru, &h->hugepage_activelist);
859
	set_page_refcounted(page);
860 861 862 863 864
	h->free_huge_pages--;
	h->free_huge_pages_node[nid]--;
	return page;
}

865 866 867
/* Movability of hugepages depends on migration support. */
static inline gfp_t htlb_alloc_mask(struct hstate *h)
{
868
	if (hugepages_treat_as_movable || hugepage_migration_supported(h))
869 870 871 872 873
		return GFP_HIGHUSER_MOVABLE;
	else
		return GFP_HIGHUSER;
}

874 875
static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
876 877
				unsigned long address, int avoid_reserve,
				long chg)
L
Linus Torvalds 已提交
878
{
879
	struct page *page = NULL;
880
	struct mempolicy *mpol;
881
	nodemask_t *nodemask;
882
	struct zonelist *zonelist;
883 884
	struct zone *zone;
	struct zoneref *z;
885
	unsigned int cpuset_mems_cookie;
L
Linus Torvalds 已提交
886

887 888 889 890 891
	/*
	 * 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
	 */
892
	if (!vma_has_reserves(vma, chg) &&
893
			h->free_huge_pages - h->resv_huge_pages == 0)
894
		goto err;
895

896
	/* If reserves cannot be used, ensure enough pages are in the pool */
897
	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
898
		goto err;
899

900
retry_cpuset:
901
	cpuset_mems_cookie = read_mems_allowed_begin();
902
	zonelist = huge_zonelist(vma, address,
903
					htlb_alloc_mask(h), &mpol, &nodemask);
904

905 906
	for_each_zone_zonelist_nodemask(zone, z, zonelist,
						MAX_NR_ZONES - 1, nodemask) {
907
		if (cpuset_zone_allowed(zone, htlb_alloc_mask(h))) {
908 909
			page = dequeue_huge_page_node(h, zone_to_nid(zone));
			if (page) {
910 911 912 913 914
				if (avoid_reserve)
					break;
				if (!vma_has_reserves(vma, chg))
					break;

915
				SetPagePrivate(page);
916
				h->resv_huge_pages--;
917 918
				break;
			}
A
Andrew Morton 已提交
919
		}
L
Linus Torvalds 已提交
920
	}
921

922
	mpol_cond_put(mpol);
923
	if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
924
		goto retry_cpuset;
L
Linus Torvalds 已提交
925
	return page;
926 927 928

err:
	return NULL;
L
Linus Torvalds 已提交
929 930
}

931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003
/*
 * 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)
{
	nid = next_node(nid, *nodes_allowed);
	if (nid == MAX_NUMNODES)
		nid = first_node(*nodes_allowed);
	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--)

1004 1005
#if defined(CONFIG_CMA) && defined(CONFIG_X86_64)
static void destroy_compound_gigantic_page(struct page *page,
1006
					unsigned int order)
1007 1008 1009 1010 1011 1012
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1013
		clear_compound_head(p);
1014 1015 1016 1017 1018 1019 1020
		set_page_refcounted(p);
	}

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

1021
static void free_gigantic_page(struct page *page, unsigned int order)
1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064
{
	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;
	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
}

static bool pfn_range_valid_gigantic(unsigned long start_pfn,
				unsigned long nr_pages)
{
	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);

		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);
}

1065
static struct page *alloc_gigantic_page(int nid, unsigned int order)
1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100
{
	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)) {
			if (pfn_range_valid_gigantic(pfn, nr_pages)) {
				/*
				 * 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);
1101
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133

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; }
1134
static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1135
static inline void destroy_compound_gigantic_page(struct page *page,
1136
						unsigned int order) { }
1137 1138 1139 1140
static inline int alloc_fresh_gigantic_page(struct hstate *h,
					nodemask_t *nodes_allowed) { return 0; }
#endif

1141
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1142 1143
{
	int i;
1144

1145 1146
	if (hstate_is_gigantic(h) && !gigantic_page_supported())
		return;
1147

1148 1149 1150
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
1151 1152
		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
1153 1154
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1155
	}
1156
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1157
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1158
	set_page_refcounted(page);
1159 1160 1161 1162 1163 1164
	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
1165 1166
}

1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177
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;
}

1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202
/*
 * 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]);
}

1203
void free_huge_page(struct page *page)
1204
{
1205 1206 1207 1208
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1209
	struct hstate *h = page_hstate(page);
1210
	int nid = page_to_nid(page);
1211 1212
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1213
	bool restore_reserve;
1214

1215
	set_page_private(page, 0);
1216
	page->mapping = NULL;
1217
	BUG_ON(page_count(page));
1218
	BUG_ON(page_mapcount(page));
1219
	restore_reserve = PagePrivate(page);
1220
	ClearPagePrivate(page);
1221

1222 1223 1224 1225 1226 1227 1228 1229
	/*
	 * 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;

1230
	spin_lock(&hugetlb_lock);
1231
	clear_page_huge_active(page);
1232 1233
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1234 1235 1236
	if (restore_reserve)
		h->resv_huge_pages++;

1237
	if (h->surplus_huge_pages_node[nid]) {
1238 1239
		/* remove the page from active list */
		list_del(&page->lru);
1240 1241 1242
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1243
	} else {
1244
		arch_clear_hugepage_flags(page);
1245
		enqueue_huge_page(h, page);
1246
	}
1247 1248 1249
	spin_unlock(&hugetlb_lock);
}

1250
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1251
{
1252
	INIT_LIST_HEAD(&page->lru);
1253
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1254
	spin_lock(&hugetlb_lock);
1255
	set_hugetlb_cgroup(page, NULL);
1256 1257
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1258 1259 1260 1261
	spin_unlock(&hugetlb_lock);
	put_page(page); /* free it into the hugepage allocator */
}

1262
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1263 1264 1265 1266 1267 1268 1269 1270
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

	/* we rely on prep_new_huge_page to set the destructor */
	set_compound_order(page, order);
	__SetPageHead(page);
1271
	__ClearPageReserved(page);
1272
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285
		/*
		 * 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);
1286
		set_page_count(p, 0);
1287
		set_compound_head(p, page);
1288 1289 1290
	}
}

A
Andrew Morton 已提交
1291 1292 1293 1294 1295
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1296 1297 1298 1299 1300 1301
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1302
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1303
}
1304 1305
EXPORT_SYMBOL_GPL(PageHuge);

1306 1307 1308 1309 1310 1311 1312 1313 1314
/*
 * 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;

1315
	return get_compound_page_dtor(page_head) == free_huge_page;
1316 1317
}

1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334
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;
}

1335
static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
L
Linus Torvalds 已提交
1336 1337
{
	struct page *page;
1338

1339
	page = __alloc_pages_node(nid,
1340
		htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1341
						__GFP_REPEAT|__GFP_NOWARN,
1342
		huge_page_order(h));
L
Linus Torvalds 已提交
1343
	if (page) {
1344
		prep_new_huge_page(h, page, nid);
L
Linus Torvalds 已提交
1345
	}
1346 1347 1348 1349

	return page;
}

1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371
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;
}

1372 1373 1374 1375 1376 1377
/*
 * 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.
 */
1378 1379
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1380
{
1381
	int nr_nodes, node;
1382 1383
	int ret = 0;

1384
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1385 1386 1387 1388
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1389 1390
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1391
			struct page *page =
1392
				list_entry(h->hugepage_freelists[node].next,
1393 1394 1395
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1396
			h->free_huge_pages_node[node]--;
1397 1398
			if (acct_surplus) {
				h->surplus_huge_pages--;
1399
				h->surplus_huge_pages_node[node]--;
1400
			}
1401 1402
			update_and_free_page(h, page);
			ret = 1;
1403
			break;
1404
		}
1405
	}
1406 1407 1408 1409

	return ret;
}

1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
 * nothing for in-use (including surplus) hugepages.
 */
static void dissolve_free_huge_page(struct page *page)
{
	spin_lock(&hugetlb_lock);
	if (PageHuge(page) && !page_count(page)) {
		struct hstate *h = page_hstate(page);
		int nid = page_to_nid(page);
		list_del(&page->lru);
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
		update_and_free_page(h, page);
	}
	spin_unlock(&hugetlb_lock);
}

/*
 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 * make specified memory blocks removable from the system.
 * Note that start_pfn should aligned with (minimum) hugepage size.
 */
void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
{
	unsigned long pfn;

1437 1438 1439
	if (!hugepages_supported())
		return;

1440 1441
	VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << minimum_order));
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order)
1442 1443 1444
		dissolve_free_huge_page(pfn_to_page(pfn));
}

1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462
/*
 * 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
1463 1464 1465 1466 1467 1468
	 * 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.
1469
	 */
D
Dave Hansen 已提交
1470
	if (!IS_ENABLED(CONFIG_NUMA) || !vma) {
1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486
		/*
		 * 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
1487 1488
	 * allocate a huge page with it.  We will only reach this
	 * when CONFIG_NUMA=y.
1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520
	 */
	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)
1521 1522
{
	struct page *page;
1523
	unsigned int r_nid;
1524

1525
	if (hstate_is_gigantic(h))
1526 1527
		return NULL;

1528 1529 1530 1531 1532 1533
	/*
	 * 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
1534 1535
		VM_WARN_ON_ONCE(addr == -1);
		VM_WARN_ON_ONCE(nid != NUMA_NO_NODE);
1536
	}
1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
	/*
	 * 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);
1561
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1562 1563 1564
		spin_unlock(&hugetlb_lock);
		return NULL;
	} else {
1565 1566
		h->nr_huge_pages++;
		h->surplus_huge_pages++;
1567 1568 1569
	}
	spin_unlock(&hugetlb_lock);

1570
	page = __hugetlb_alloc_buddy_huge_page(h, vma, addr, nid);
1571 1572

	spin_lock(&hugetlb_lock);
1573
	if (page) {
1574
		INIT_LIST_HEAD(&page->lru);
1575
		r_nid = page_to_nid(page);
1576
		set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1577
		set_hugetlb_cgroup(page, NULL);
1578 1579 1580
		/*
		 * We incremented the global counters already
		 */
1581 1582
		h->nr_huge_pages_node[r_nid]++;
		h->surplus_huge_pages_node[r_nid]++;
1583
		__count_vm_event(HTLB_BUDDY_PGALLOC);
1584
	} else {
1585 1586
		h->nr_huge_pages--;
		h->surplus_huge_pages--;
1587
		__count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1588
	}
1589
	spin_unlock(&hugetlb_lock);
1590 1591 1592 1593

	return page;
}

1594 1595 1596 1597 1598
/*
 * 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
1599
static
1600 1601 1602 1603 1604 1605 1606 1607 1608 1609
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
1610
static
1611 1612 1613 1614 1615 1616
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);
}

1617 1618 1619 1620 1621 1622 1623
/*
 * 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)
{
1624
	struct page *page = NULL;
1625 1626

	spin_lock(&hugetlb_lock);
1627 1628
	if (h->free_huge_pages - h->resv_huge_pages > 0)
		page = dequeue_huge_page_node(h, nid);
1629 1630
	spin_unlock(&hugetlb_lock);

1631
	if (!page)
1632
		page = __alloc_buddy_huge_page_no_mpol(h, nid);
1633 1634 1635 1636

	return page;
}

1637
/*
L
Lucas De Marchi 已提交
1638
 * Increase the hugetlb pool such that it can accommodate a reservation
1639 1640
 * of size 'delta'.
 */
1641
static int gather_surplus_pages(struct hstate *h, int delta)
1642 1643 1644 1645 1646
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
1647
	bool alloc_ok = true;
1648

1649
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1650
	if (needed <= 0) {
1651
		h->resv_huge_pages += delta;
1652
		return 0;
1653
	}
1654 1655 1656 1657 1658 1659 1660 1661

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
1662
		page = __alloc_buddy_huge_page_no_mpol(h, NUMA_NO_NODE);
1663 1664 1665 1666
		if (!page) {
			alloc_ok = false;
			break;
		}
1667 1668
		list_add(&page->lru, &surplus_list);
	}
1669
	allocated += i;
1670 1671 1672 1673 1674 1675

	/*
	 * 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);
1676 1677
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
1678 1679 1680 1681 1682 1683 1684 1685 1686 1687
	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;
	}
1688 1689
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
1690
	 * needed to accommodate the reservation.  Add the appropriate number
1691
	 * of pages to the hugetlb pool and free the extras back to the buddy
1692 1693 1694
	 * 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.
1695 1696
	 */
	needed += allocated;
1697
	h->resv_huge_pages += delta;
1698
	ret = 0;
1699

1700
	/* Free the needed pages to the hugetlb pool */
1701
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1702 1703
		if ((--needed) < 0)
			break;
1704 1705 1706 1707 1708
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
1709
		VM_BUG_ON_PAGE(page_count(page), page);
1710
		enqueue_huge_page(h, page);
1711
	}
1712
free:
1713
	spin_unlock(&hugetlb_lock);
1714 1715

	/* Free unnecessary surplus pages to the buddy allocator */
1716 1717
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
1718
	spin_lock(&hugetlb_lock);
1719 1720 1721 1722 1723 1724 1725 1726

	return ret;
}

/*
 * When releasing a hugetlb pool reservation, any surplus pages that were
 * allocated to satisfy the reservation must be explicitly freed if they were
 * never used.
1727
 * Called with hugetlb_lock held.
1728
 */
1729 1730
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
1731 1732 1733
{
	unsigned long nr_pages;

1734
	/* Uncommit the reservation */
1735
	h->resv_huge_pages -= unused_resv_pages;
1736

1737
	/* Cannot return gigantic pages currently */
1738
	if (hstate_is_gigantic(h))
1739 1740
		return;

1741
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1742

1743 1744
	/*
	 * We want to release as many surplus pages as possible, spread
1745 1746 1747 1748 1749
	 * 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.
1750 1751
	 */
	while (nr_pages--) {
1752
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1753
			break;
1754
		cond_resched_lock(&hugetlb_lock);
1755 1756 1757
	}
}

1758

1759
/*
1760
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1761
 * are used by the huge page allocation routines to manage reservations.
1762 1763 1764 1765 1766 1767
 *
 * 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
1768 1769 1770
 * 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.
1771 1772 1773 1774 1775 1776
 *
 * 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.
1777
 */
1778 1779 1780
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
1781
	VMA_END_RESV,
1782
};
1783 1784
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
1785
				enum vma_resv_mode mode)
1786
{
1787 1788
	struct resv_map *resv;
	pgoff_t idx;
1789
	long ret;
1790

1791 1792
	resv = vma_resv_map(vma);
	if (!resv)
1793
		return 1;
1794

1795
	idx = vma_hugecache_offset(h, vma, addr);
1796 1797
	switch (mode) {
	case VMA_NEEDS_RESV:
1798
		ret = region_chg(resv, idx, idx + 1);
1799 1800 1801 1802
		break;
	case VMA_COMMIT_RESV:
		ret = region_add(resv, idx, idx + 1);
		break;
1803
	case VMA_END_RESV:
1804 1805 1806 1807 1808 1809
		region_abort(resv, idx, idx + 1);
		ret = 0;
		break;
	default:
		BUG();
	}
1810

1811
	if (vma->vm_flags & VM_MAYSHARE)
1812
		return ret;
1813
	else
1814
		return ret < 0 ? ret : 0;
1815
}
1816 1817

static long vma_needs_reservation(struct hstate *h,
1818
			struct vm_area_struct *vma, unsigned long addr)
1819
{
1820
	return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
1821
}
1822

1823 1824 1825
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
1826 1827 1828
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

1829
static void vma_end_reservation(struct hstate *h,
1830 1831
			struct vm_area_struct *vma, unsigned long addr)
{
1832
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
1833 1834
}

1835
struct page *alloc_huge_page(struct vm_area_struct *vma,
1836
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
1837
{
1838
	struct hugepage_subpool *spool = subpool_vma(vma);
1839
	struct hstate *h = hstate_vma(vma);
1840
	struct page *page;
1841 1842
	long map_chg, map_commit;
	long gbl_chg;
1843 1844
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
1845

1846
	idx = hstate_index(h);
1847
	/*
1848 1849 1850
	 * 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).
1851
	 */
1852 1853
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
1854
		return ERR_PTR(-ENOMEM);
1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865

	/*
	 * 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) {
1866
			vma_end_reservation(h, vma, addr);
1867
			return ERR_PTR(-ENOSPC);
1868
		}
L
Linus Torvalds 已提交
1869

1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881
		/*
		 * 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;
	}

1882
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1883 1884 1885
	if (ret)
		goto out_subpool_put;

L
Linus Torvalds 已提交
1886
	spin_lock(&hugetlb_lock);
1887 1888 1889 1890 1891 1892
	/*
	 * 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);
1893
	if (!page) {
1894
		spin_unlock(&hugetlb_lock);
1895
		page = __alloc_buddy_huge_page_with_mpol(h, vma, addr);
1896 1897
		if (!page)
			goto out_uncharge_cgroup;
1898 1899 1900 1901
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
1902 1903
		spin_lock(&hugetlb_lock);
		list_move(&page->lru, &h->hugepage_activelist);
1904
		/* Fall through */
K
Ken Chen 已提交
1905
	}
1906 1907
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
	spin_unlock(&hugetlb_lock);
1908

1909
	set_page_private(page, (unsigned long)spool);
1910

1911 1912
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926
		/*
		 * 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);
	}
1927
	return page;
1928 1929 1930 1931

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
out_subpool_put:
1932
	if (map_chg || avoid_reserve)
1933
		hugepage_subpool_put_pages(spool, 1);
1934
	vma_end_reservation(h, vma, addr);
1935
	return ERR_PTR(-ENOSPC);
1936 1937
}

1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951
/*
 * 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;
}

1952
int __weak alloc_bootmem_huge_page(struct hstate *h)
1953 1954
{
	struct huge_bootmem_page *m;
1955
	int nr_nodes, node;
1956

1957
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
1958 1959
		void *addr;

1960 1961 1962
		addr = memblock_virt_alloc_try_nid_nopanic(
				huge_page_size(h), huge_page_size(h),
				0, BOOTMEM_ALLOC_ACCESSIBLE, node);
1963 1964 1965 1966 1967 1968 1969
		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;
1970
			goto found;
1971 1972 1973 1974 1975
		}
	}
	return 0;

found:
1976
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
1977 1978 1979 1980 1981 1982
	/* 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;
}

1983 1984
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
1985 1986 1987 1988 1989 1990 1991
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

1992 1993 1994 1995 1996 1997 1998
/* 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;
1999 2000 2001 2002
		struct page *page;

#ifdef CONFIG_HIGHMEM
		page = pfn_to_page(m->phys >> PAGE_SHIFT);
2003 2004
		memblock_free_late(__pa(m),
				   sizeof(struct huge_bootmem_page));
2005 2006 2007
#else
		page = virt_to_page(m);
#endif
2008
		WARN_ON(page_count(page) != 1);
2009
		prep_compound_huge_page(page, h->order);
2010
		WARN_ON(PageReserved(page));
2011
		prep_new_huge_page(h, page, page_to_nid(page));
2012 2013 2014 2015 2016 2017
		/*
		 * 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.
		 */
2018
		if (hstate_is_gigantic(h))
2019
			adjust_managed_page_count(page, 1 << h->order);
2020 2021 2022
	}
}

2023
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2024 2025
{
	unsigned long i;
2026

2027
	for (i = 0; i < h->max_huge_pages; ++i) {
2028
		if (hstate_is_gigantic(h)) {
2029 2030
			if (!alloc_bootmem_huge_page(h))
				break;
2031
		} else if (!alloc_fresh_huge_page(h,
2032
					 &node_states[N_MEMORY]))
L
Linus Torvalds 已提交
2033 2034
			break;
	}
2035
	h->max_huge_pages = i;
2036 2037 2038 2039 2040 2041 2042
}

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

	for_each_hstate(h) {
2043 2044 2045
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2046
		/* oversize hugepages were init'ed in early boot */
2047
		if (!hstate_is_gigantic(h))
2048
			hugetlb_hstate_alloc_pages(h);
2049
	}
2050
	VM_BUG_ON(minimum_order == UINT_MAX);
2051 2052
}

A
Andi Kleen 已提交
2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063
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;
}

2064 2065 2066 2067 2068
static void __init report_hugepages(void)
{
	struct hstate *h;

	for_each_hstate(h) {
A
Andi Kleen 已提交
2069
		char buf[32];
2070
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
A
Andi Kleen 已提交
2071 2072
			memfmt(buf, huge_page_size(h)),
			h->free_huge_pages);
2073 2074 2075
	}
}

L
Linus Torvalds 已提交
2076
#ifdef CONFIG_HIGHMEM
2077 2078
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2079
{
2080 2081
	int i;

2082
	if (hstate_is_gigantic(h))
2083 2084
		return;

2085
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2086
		struct page *page, *next;
2087 2088 2089
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2090
				return;
L
Linus Torvalds 已提交
2091 2092 2093
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2094
			update_and_free_page(h, page);
2095 2096
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2097 2098 2099 2100
		}
	}
}
#else
2101 2102
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2103 2104 2105 2106
{
}
#endif

2107 2108 2109 2110 2111
/*
 * 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.
 */
2112 2113
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2114
{
2115
	int nr_nodes, node;
2116 2117 2118

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

2119 2120 2121 2122
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2123
		}
2124 2125 2126 2127 2128
	} 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;
2129
		}
2130 2131
	}
	return 0;
2132

2133 2134 2135 2136
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2137 2138
}

2139
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2140 2141
static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2142
{
2143
	unsigned long min_count, ret;
L
Linus Torvalds 已提交
2144

2145
	if (hstate_is_gigantic(h) && !gigantic_page_supported())
2146 2147
		return h->max_huge_pages;

2148 2149 2150 2151
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2152
	 *
N
Naoya Horiguchi 已提交
2153
	 * We might race with __alloc_buddy_huge_page() here and be unable
2154 2155 2156 2157
	 * 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.
2158
	 */
L
Linus Torvalds 已提交
2159
	spin_lock(&hugetlb_lock);
2160
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2161
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2162 2163 2164
			break;
	}

2165
	while (count > persistent_huge_pages(h)) {
2166 2167 2168 2169 2170 2171
		/*
		 * 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);
2172 2173 2174 2175
		if (hstate_is_gigantic(h))
			ret = alloc_fresh_gigantic_page(h, nodes_allowed);
		else
			ret = alloc_fresh_huge_page(h, nodes_allowed);
2176 2177 2178 2179
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2180 2181 2182
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2183 2184 2185 2186 2187 2188 2189 2190
	}

	/*
	 * 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.
2191 2192 2193 2194
	 *
	 * 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
2195
	 * __alloc_buddy_huge_page() is checking the global counter,
2196 2197 2198
	 * 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.
2199
	 */
2200
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2201
	min_count = max(count, min_count);
2202
	try_to_free_low(h, min_count, nodes_allowed);
2203
	while (min_count < persistent_huge_pages(h)) {
2204
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2205
			break;
2206
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2207
	}
2208
	while (count < persistent_huge_pages(h)) {
2209
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2210 2211 2212
			break;
	}
out:
2213
	ret = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2214
	spin_unlock(&hugetlb_lock);
2215
	return ret;
L
Linus Torvalds 已提交
2216 2217
}

2218 2219 2220 2221 2222 2223 2224 2225 2226 2227
#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];

2228 2229 2230
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2231 2232
{
	int i;
2233

2234
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2235 2236 2237
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2238
			return &hstates[i];
2239 2240 2241
		}

	return kobj_to_node_hstate(kobj, nidp);
2242 2243
}

2244
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2245 2246
					struct kobj_attribute *attr, char *buf)
{
2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257
	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);
2258
}
2259

2260 2261 2262
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2263 2264
{
	int err;
2265
	NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
2266

2267
	if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
2268 2269 2270 2271
		err = -EINVAL;
		goto out;
	}

2272 2273 2274 2275 2276 2277 2278
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
				init_nodemask_of_mempolicy(nodes_allowed))) {
			NODEMASK_FREE(nodes_allowed);
2279
			nodes_allowed = &node_states[N_MEMORY];
2280 2281 2282 2283 2284 2285 2286 2287 2288
		}
	} 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
2289
		nodes_allowed = &node_states[N_MEMORY];
2290

2291
	h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
2292

2293
	if (nodes_allowed != &node_states[N_MEMORY])
2294 2295 2296
		NODEMASK_FREE(nodes_allowed);

	return len;
2297 2298 2299
out:
	NODEMASK_FREE(nodes_allowed);
	return err;
2300 2301
}

2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318
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);
}

2319 2320 2321 2322 2323 2324 2325 2326 2327
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)
{
2328
	return nr_hugepages_store_common(false, kobj, buf, len);
2329 2330 2331
}
HSTATE_ATTR(nr_hugepages);

2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346
#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)
{
2347
	return nr_hugepages_store_common(true, kobj, buf, len);
2348 2349 2350 2351 2352
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2353 2354 2355
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2356
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2357 2358
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2359

2360 2361 2362 2363 2364
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;
2365
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2366

2367
	if (hstate_is_gigantic(h))
2368 2369
		return -EINVAL;

2370
	err = kstrtoul(buf, 10, &input);
2371
	if (err)
2372
		return err;
2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384

	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)
{
2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395
	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);
2396 2397 2398 2399 2400 2401
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2402
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2403 2404 2405 2406 2407 2408 2409
	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)
{
2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420
	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);
2421 2422 2423 2424 2425 2426 2427 2428 2429
}
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,
2430 2431 2432
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
2433 2434 2435 2436 2437 2438 2439
	NULL,
};

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

J
Jeff Mahoney 已提交
2440 2441 2442
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
				    struct attribute_group *hstate_attr_group)
2443 2444
{
	int retval;
2445
	int hi = hstate_index(h);
2446

2447 2448
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
2449 2450
		return -ENOMEM;

2451
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2452
	if (retval)
2453
		kobject_put(hstate_kobjs[hi]);
2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467

	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) {
2468 2469
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
2470
		if (err)
2471
			pr_err("Hugetlb: Unable to add hstate %s", h->name);
2472 2473 2474
	}
}

2475 2476 2477 2478
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2479 2480 2481
 * 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
2482 2483 2484 2485 2486 2487
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
2488
static struct node_hstate node_hstates[MAX_NUMNODES];
2489 2490

/*
2491
 * A subset of global hstate attributes for node devices
2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504
 */
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,
};

/*
2505
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527
 * 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;
}

/*
2528
 * Unregister hstate attributes from a single node device.
2529 2530
 * No-op if no hstate attributes attached.
 */
2531
static void hugetlb_unregister_node(struct node *node)
2532 2533
{
	struct hstate *h;
2534
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2535 2536

	if (!nhs->hugepages_kobj)
2537
		return;		/* no hstate attributes */
2538

2539 2540 2541 2542 2543
	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;
2544
		}
2545
	}
2546 2547 2548 2549 2550 2551 2552

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


/*
2553
 * Register hstate attributes for a single node device.
2554 2555
 * No-op if attributes already registered.
 */
2556
static void hugetlb_register_node(struct node *node)
2557 2558
{
	struct hstate *h;
2559
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2560 2561 2562 2563 2564 2565
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2566
							&node->dev.kobj);
2567 2568 2569 2570 2571 2572 2573 2574
	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) {
2575 2576
			pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
				h->name, node->dev.id);
2577 2578 2579 2580 2581 2582 2583
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
2584
 * hugetlb init time:  register hstate attributes for all registered node
2585 2586
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
2587
 */
2588
static void __init hugetlb_register_all_nodes(void)
2589 2590 2591
{
	int nid;

2592
	for_each_node_state(nid, N_MEMORY) {
2593
		struct node *node = node_devices[nid];
2594
		if (node->dev.id == nid)
2595 2596 2597 2598
			hugetlb_register_node(node);
	}

	/*
2599
	 * Let the node device driver know we're here so it can
2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618
	 * [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

2619 2620
static int __init hugetlb_init(void)
{
2621 2622
	int i;

2623
	if (!hugepages_supported())
2624
		return 0;
2625

2626 2627 2628 2629
	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);
2630
	}
2631
	default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2632 2633
	if (default_hstate_max_huge_pages)
		default_hstate.max_huge_pages = default_hstate_max_huge_pages;
2634 2635

	hugetlb_init_hstates();
2636
	gather_bootmem_prealloc();
2637 2638 2639
	report_hugepages();

	hugetlb_sysfs_init();
2640
	hugetlb_register_all_nodes();
2641
	hugetlb_cgroup_file_init();
2642

2643 2644 2645 2646 2647
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
2648
	hugetlb_fault_mutex_table =
2649
		kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2650
	BUG_ON(!hugetlb_fault_mutex_table);
2651 2652

	for (i = 0; i < num_fault_mutexes; i++)
2653
		mutex_init(&hugetlb_fault_mutex_table[i]);
2654 2655
	return 0;
}
2656
subsys_initcall(hugetlb_init);
2657 2658

/* Should be called on processing a hugepagesz=... option */
2659
void __init hugetlb_add_hstate(unsigned int order)
2660 2661
{
	struct hstate *h;
2662 2663
	unsigned long i;

2664
	if (size_to_hstate(PAGE_SIZE << order)) {
2665
		pr_warning("hugepagesz= specified twice, ignoring\n");
2666 2667
		return;
	}
2668
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2669
	BUG_ON(order == 0);
2670
	h = &hstates[hugetlb_max_hstate++];
2671 2672
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2673 2674 2675 2676
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2677
	INIT_LIST_HEAD(&h->hugepage_activelist);
2678 2679
	h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
	h->next_nid_to_free = first_node(node_states[N_MEMORY]);
2680 2681
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
2682

2683 2684 2685
	parsed_hstate = h;
}

2686
static int __init hugetlb_nrpages_setup(char *s)
2687 2688
{
	unsigned long *mhp;
2689
	static unsigned long *last_mhp;
2690 2691

	/*
2692
	 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2693 2694
	 * so this hugepages= parameter goes to the "default hstate".
	 */
2695
	if (!hugetlb_max_hstate)
2696 2697 2698 2699
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

2700
	if (mhp == last_mhp) {
2701 2702
		pr_warning("hugepages= specified twice without "
			   "interleaving hugepagesz=, ignoring\n");
2703 2704 2705
		return 1;
	}

2706 2707 2708
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

2709 2710 2711 2712 2713
	/*
	 * 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.
	 */
2714
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2715 2716 2717 2718
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

2719 2720
	return 1;
}
2721 2722 2723 2724 2725 2726 2727 2728
__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);
2729

2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741
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
2742 2743 2744
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
2745
{
2746
	struct hstate *h = &default_hstate;
2747
	unsigned long tmp = h->max_huge_pages;
2748
	int ret;
2749

2750 2751 2752
	if (!hugepages_supported())
		return -ENOTSUPP;

2753 2754
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2755 2756 2757
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2758

2759 2760 2761
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
2762 2763
out:
	return ret;
L
Linus Torvalds 已提交
2764
}
2765

2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782
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 */

2783
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2784
			void __user *buffer,
2785 2786
			size_t *length, loff_t *ppos)
{
2787
	struct hstate *h = &default_hstate;
2788
	unsigned long tmp;
2789
	int ret;
2790

2791 2792 2793
	if (!hugepages_supported())
		return -ENOTSUPP;

2794
	tmp = h->nr_overcommit_huge_pages;
2795

2796
	if (write && hstate_is_gigantic(h))
2797 2798
		return -EINVAL;

2799 2800
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2801 2802 2803
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2804 2805 2806 2807 2808 2809

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
2810 2811
out:
	return ret;
2812 2813
}

L
Linus Torvalds 已提交
2814 2815
#endif /* CONFIG_SYSCTL */

2816
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
2817
{
2818
	struct hstate *h = &default_hstate;
2819 2820
	if (!hugepages_supported())
		return;
2821
	seq_printf(m,
2822 2823 2824 2825 2826
			"HugePages_Total:   %5lu\n"
			"HugePages_Free:    %5lu\n"
			"HugePages_Rsvd:    %5lu\n"
			"HugePages_Surp:    %5lu\n"
			"Hugepagesize:   %8lu kB\n",
2827 2828 2829 2830 2831
			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
2832 2833 2834 2835
}

int hugetlb_report_node_meminfo(int nid, char *buf)
{
2836
	struct hstate *h = &default_hstate;
2837 2838
	if (!hugepages_supported())
		return 0;
L
Linus Torvalds 已提交
2839 2840
	return sprintf(buf,
		"Node %d HugePages_Total: %5u\n"
2841 2842
		"Node %d HugePages_Free:  %5u\n"
		"Node %d HugePages_Surp:  %5u\n",
2843 2844 2845
		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
2846 2847
}

2848 2849 2850 2851 2852
void hugetlb_show_meminfo(void)
{
	struct hstate *h;
	int nid;

2853 2854 2855
	if (!hugepages_supported())
		return;

2856 2857 2858 2859 2860 2861 2862 2863 2864 2865
	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));
}

2866 2867 2868 2869 2870 2871
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
2872 2873 2874
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
2875 2876 2877 2878 2879 2880
	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
2881 2882
}

2883
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905
{
	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) {
2906
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
2907 2908
			goto out;

2909 2910
		if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
2911 2912 2913 2914 2915 2916
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
2917
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
2918 2919 2920 2921 2922 2923

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

2924 2925
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
2926
	struct resv_map *resv = vma_resv_map(vma);
2927 2928 2929 2930 2931

	/*
	 * 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
2932
	 * has a reference to the reservation map it cannot disappear until
2933 2934 2935
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
2936
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
2937
		kref_get(&resv->refs);
2938 2939
}

2940 2941
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
2942
	struct hstate *h = hstate_vma(vma);
2943
	struct resv_map *resv = vma_resv_map(vma);
2944
	struct hugepage_subpool *spool = subpool_vma(vma);
2945
	unsigned long reserve, start, end;
2946
	long gbl_reserve;
2947

2948 2949
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
2950

2951 2952
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
2953

2954
	reserve = (end - start) - region_count(resv, start, end);
2955

2956 2957 2958
	kref_put(&resv->refs, resv_map_release);

	if (reserve) {
2959 2960 2961 2962 2963 2964
		/*
		 * 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);
2965
	}
2966 2967
}

L
Linus Torvalds 已提交
2968 2969 2970 2971 2972 2973
/*
 * We cannot handle pagefaults against hugetlb pages at all.  They cause
 * handle_mm_fault() to try to instantiate regular-sized pages in the
 * hugegpage VMA.  do_page_fault() is supposed to trap this, so BUG is we get
 * this far.
 */
N
Nick Piggin 已提交
2974
static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
L
Linus Torvalds 已提交
2975 2976
{
	BUG();
N
Nick Piggin 已提交
2977
	return 0;
L
Linus Torvalds 已提交
2978 2979
}

2980
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
2981
	.fault = hugetlb_vm_op_fault,
2982
	.open = hugetlb_vm_op_open,
2983
	.close = hugetlb_vm_op_close,
L
Linus Torvalds 已提交
2984 2985
};

2986 2987
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
2988 2989 2990
{
	pte_t entry;

2991
	if (writable) {
2992 2993
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
2994
	} else {
2995 2996
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
2997 2998 2999
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3000
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3001 3002 3003 3004

	return entry;
}

3005 3006 3007 3008 3009
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3010
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3011
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3012
		update_mmu_cache(vma, address, ptep);
3013 3014
}

3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039
static int is_hugetlb_entry_migration(pte_t pte)
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
		return 0;
	swp = pte_to_swp_entry(pte);
	if (non_swap_entry(swp) && is_migration_entry(swp))
		return 1;
	else
		return 0;
}

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;
}
3040

D
David Gibson 已提交
3041 3042 3043 3044 3045
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;
3046
	unsigned long addr;
3047
	int cow;
3048 3049
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3050 3051 3052
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
	int ret = 0;
3053 3054

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3055

3056 3057 3058 3059 3060
	mmun_start = vma->vm_start;
	mmun_end = vma->vm_end;
	if (cow)
		mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);

3061
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3062
		spinlock_t *src_ptl, *dst_ptl;
H
Hugh Dickins 已提交
3063 3064 3065
		src_pte = huge_pte_offset(src, addr);
		if (!src_pte)
			continue;
3066
		dst_pte = huge_pte_alloc(dst, addr, sz);
3067 3068 3069 3070
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3071 3072 3073 3074 3075

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

3076 3077 3078
		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);
3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096
		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 {
3097
			if (cow) {
3098
				huge_ptep_set_wrprotect(src, addr, src_pte);
3099 3100 3101
				mmu_notifier_invalidate_range(src, mmun_start,
								   mmun_end);
			}
3102
			entry = huge_ptep_get(src_pte);
3103 3104
			ptepage = pte_page(entry);
			get_page(ptepage);
3105
			page_dup_rmap(ptepage);
3106
			set_huge_pte_at(dst, addr, dst_pte, entry);
3107
			hugetlb_count_add(pages_per_huge_page(h), dst);
3108
		}
3109 3110
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3111 3112
	}

3113 3114 3115 3116
	if (cow)
		mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);

	return ret;
D
David Gibson 已提交
3117 3118
}

3119 3120 3121
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
3122
{
3123
	int force_flush = 0;
D
David Gibson 已提交
3124 3125
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3126
	pte_t *ptep;
D
David Gibson 已提交
3127
	pte_t pte;
3128
	spinlock_t *ptl;
D
David Gibson 已提交
3129
	struct page *page;
3130 3131
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3132 3133
	const unsigned long mmun_start = start;	/* For mmu_notifiers */
	const unsigned long mmun_end   = end;	/* For mmu_notifiers */
3134

D
David Gibson 已提交
3135
	WARN_ON(!is_vm_hugetlb_page(vma));
3136 3137
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3138

3139
	tlb_start_vma(tlb, vma);
3140
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3141
	address = start;
3142
again:
3143
	for (; address < end; address += sz) {
3144
		ptep = huge_pte_offset(mm, address);
A
Adam Litke 已提交
3145
		if (!ptep)
3146 3147
			continue;

3148
		ptl = huge_pte_lock(h, mm, ptep);
3149
		if (huge_pmd_unshare(mm, &address, ptep))
3150
			goto unlock;
3151

3152 3153
		pte = huge_ptep_get(ptep);
		if (huge_pte_none(pte))
3154
			goto unlock;
3155 3156

		/*
3157 3158
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3159
		 */
3160
		if (unlikely(!pte_present(pte))) {
3161
			huge_pte_clear(mm, address, ptep);
3162
			goto unlock;
3163
		}
3164 3165

		page = pte_page(pte);
3166 3167 3168 3169 3170 3171 3172
		/*
		 * If a reference page is supplied, it is because a specific
		 * page is being unmapped, not a range. Ensure the page we
		 * are about to unmap is the actual page of interest.
		 */
		if (ref_page) {
			if (page != ref_page)
3173
				goto unlock;
3174 3175 3176 3177 3178 3179 3180 3181 3182

			/*
			 * 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);
		}

3183
		pte = huge_ptep_get_and_clear(mm, address, ptep);
3184
		tlb_remove_tlb_entry(tlb, ptep, address);
3185
		if (huge_pte_dirty(pte))
3186
			set_page_dirty(page);
3187

3188
		hugetlb_count_sub(pages_per_huge_page(h), mm);
3189 3190
		page_remove_rmap(page);
		force_flush = !__tlb_remove_page(tlb, page);
3191
		if (force_flush) {
3192
			address += sz;
3193
			spin_unlock(ptl);
3194
			break;
3195
		}
3196
		/* Bail out after unmapping reference page if supplied */
3197 3198
		if (ref_page) {
			spin_unlock(ptl);
3199
			break;
3200 3201 3202
		}
unlock:
		spin_unlock(ptl);
D
David Gibson 已提交
3203
	}
3204 3205 3206 3207 3208 3209 3210 3211 3212 3213
	/*
	 * mmu_gather ran out of room to batch pages, we break out of
	 * the PTE lock to avoid doing the potential expensive TLB invalidate
	 * and page-free while holding it.
	 */
	if (force_flush) {
		force_flush = 0;
		tlb_flush_mmu(tlb);
		if (address < end && !ref_page)
			goto again;
3214
	}
3215
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3216
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
3217
}
D
David Gibson 已提交
3218

3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230
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
3231
	 * is to clear it before releasing the i_mmap_rwsem. This works
3232
	 * because in the context this is called, the VMA is about to be
3233
	 * destroyed and the i_mmap_rwsem is held.
3234 3235 3236 3237
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

3238
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3239
			  unsigned long end, struct page *ref_page)
3240
{
3241 3242 3243 3244 3245
	struct mm_struct *mm;
	struct mmu_gather tlb;

	mm = vma->vm_mm;

3246
	tlb_gather_mmu(&tlb, mm, start, end);
3247 3248
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
	tlb_finish_mmu(&tlb, start, end);
3249 3250
}

3251 3252 3253 3254 3255 3256
/*
 * 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.
 */
3257 3258
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
3259
{
3260
	struct hstate *h = hstate_vma(vma);
3261 3262 3263 3264 3265 3266 3267 3268
	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.
	 */
3269
	address = address & huge_page_mask(h);
3270 3271
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
A
Al Viro 已提交
3272
	mapping = file_inode(vma->vm_file)->i_mapping;
3273

3274 3275 3276 3277 3278
	/*
	 * 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
	 */
3279
	i_mmap_lock_write(mapping);
3280
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3281 3282 3283 3284
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

3285 3286 3287 3288 3289 3290 3291 3292
		/*
		 * 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;

3293 3294 3295 3296 3297 3298 3299 3300
		/*
		 * 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))
3301 3302
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
3303
	}
3304
	i_mmap_unlock_write(mapping);
3305 3306
}

3307 3308
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3309 3310 3311
 * 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.
3312
 */
3313
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3314
			unsigned long address, pte_t *ptep, pte_t pte,
3315
			struct page *pagecache_page, spinlock_t *ptl)
3316
{
3317
	struct hstate *h = hstate_vma(vma);
3318
	struct page *old_page, *new_page;
3319
	int ret = 0, outside_reserve = 0;
3320 3321
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
3322 3323 3324

	old_page = pte_page(pte);

3325
retry_avoidcopy:
3326 3327
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
3328 3329
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
		page_move_anon_rmap(old_page, vma, address);
3330
		set_huge_ptep_writable(vma, address, ptep);
N
Nick Piggin 已提交
3331
		return 0;
3332 3333
	}

3334 3335 3336 3337 3338 3339 3340 3341 3342
	/*
	 * 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.
	 */
3343
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3344 3345 3346
			old_page != pagecache_page)
		outside_reserve = 1;

3347
	page_cache_get(old_page);
3348

3349 3350 3351 3352
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
3353
	spin_unlock(ptl);
3354
	new_page = alloc_huge_page(vma, address, outside_reserve);
3355

3356
	if (IS_ERR(new_page)) {
3357 3358 3359 3360 3361 3362 3363 3364
		/*
		 * 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) {
3365
			page_cache_release(old_page);
3366
			BUG_ON(huge_pte_none(pte));
3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378
			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;
3379 3380
		}

3381 3382 3383
		ret = (PTR_ERR(new_page) == -ENOMEM) ?
			VM_FAULT_OOM : VM_FAULT_SIGBUS;
		goto out_release_old;
3384 3385
	}

3386 3387 3388 3389
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
3390
	if (unlikely(anon_vma_prepare(vma))) {
3391 3392
		ret = VM_FAULT_OOM;
		goto out_release_all;
3393
	}
3394

A
Andrea Arcangeli 已提交
3395 3396
	copy_user_huge_page(new_page, old_page, address, vma,
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
3397
	__SetPageUptodate(new_page);
3398
	set_page_huge_active(new_page);
3399

3400 3401 3402
	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);
3403

3404
	/*
3405
	 * Retake the page table lock to check for racing updates
3406 3407
	 * before the page tables are altered
	 */
3408
	spin_lock(ptl);
3409
	ptep = huge_pte_offset(mm, address & huge_page_mask(h));
3410
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3411 3412
		ClearPagePrivate(new_page);

3413
		/* Break COW */
3414
		huge_ptep_clear_flush(vma, address, ptep);
3415
		mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
3416 3417
		set_huge_pte_at(mm, address, ptep,
				make_huge_pte(vma, new_page, 1));
3418
		page_remove_rmap(old_page);
3419
		hugepage_add_new_anon_rmap(new_page, vma, address);
3420 3421 3422
		/* Make the old page be freed below */
		new_page = old_page;
	}
3423
	spin_unlock(ptl);
3424
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3425
out_release_all:
3426
	page_cache_release(new_page);
3427
out_release_old:
3428
	page_cache_release(old_page);
3429

3430 3431
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
3432 3433
}

3434
/* Return the pagecache page at a given address within a VMA */
3435 3436
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
3437 3438
{
	struct address_space *mapping;
3439
	pgoff_t idx;
3440 3441

	mapping = vma->vm_file->f_mapping;
3442
	idx = vma_hugecache_offset(h, vma, address);
3443 3444 3445 3446

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
3447 3448 3449 3450 3451
/*
 * 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
3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466
			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;
}

3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483
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;
}

3484
static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
3485 3486
			   struct address_space *mapping, pgoff_t idx,
			   unsigned long address, pte_t *ptep, unsigned int flags)
3487
{
3488
	struct hstate *h = hstate_vma(vma);
3489
	int ret = VM_FAULT_SIGBUS;
3490
	int anon_rmap = 0;
A
Adam Litke 已提交
3491 3492
	unsigned long size;
	struct page *page;
3493
	pte_t new_pte;
3494
	spinlock_t *ptl;
A
Adam Litke 已提交
3495

3496 3497 3498
	/*
	 * 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
3499
	 * COW. Warn that such a situation has occurred as it may not be obvious
3500 3501
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3502 3503
		pr_warning("PID %d killed due to inadequate hugepage pool\n",
			   current->pid);
3504 3505 3506
		return ret;
	}

A
Adam Litke 已提交
3507 3508 3509 3510
	/*
	 * Use page lock to guard against racing truncation
	 * before we get page_table_lock.
	 */
3511 3512 3513
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
3514
		size = i_size_read(mapping->host) >> huge_page_shift(h);
3515 3516
		if (idx >= size)
			goto out;
3517
		page = alloc_huge_page(vma, address, 0);
3518
		if (IS_ERR(page)) {
3519 3520 3521 3522 3523
			ret = PTR_ERR(page);
			if (ret == -ENOMEM)
				ret = VM_FAULT_OOM;
			else
				ret = VM_FAULT_SIGBUS;
3524 3525
			goto out;
		}
A
Andrea Arcangeli 已提交
3526
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
3527
		__SetPageUptodate(page);
3528
		set_page_huge_active(page);
3529

3530
		if (vma->vm_flags & VM_MAYSHARE) {
3531
			int err = huge_add_to_page_cache(page, mapping, idx);
3532 3533 3534 3535 3536 3537
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
3538
		} else {
3539
			lock_page(page);
3540 3541 3542 3543
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
3544
			anon_rmap = 1;
3545
		}
3546
	} else {
3547 3548 3549 3550 3551 3552
		/*
		 * 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))) {
3553
			ret = VM_FAULT_HWPOISON |
3554
				VM_FAULT_SET_HINDEX(hstate_index(h));
3555 3556
			goto backout_unlocked;
		}
3557
	}
3558

3559 3560 3561 3562 3563 3564
	/*
	 * 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.
	 */
3565
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3566 3567 3568 3569
		if (vma_needs_reservation(h, vma, address) < 0) {
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
3570
		/* Just decrements count, does not deallocate */
3571
		vma_end_reservation(h, vma, address);
3572
	}
3573

3574 3575
	ptl = huge_pte_lockptr(h, mm, ptep);
	spin_lock(ptl);
3576
	size = i_size_read(mapping->host) >> huge_page_shift(h);
A
Adam Litke 已提交
3577 3578 3579
	if (idx >= size)
		goto backout;

N
Nick Piggin 已提交
3580
	ret = 0;
3581
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
3582 3583
		goto backout;

3584 3585
	if (anon_rmap) {
		ClearPagePrivate(page);
3586
		hugepage_add_new_anon_rmap(page, vma, address);
3587
	} else
3588
		page_dup_rmap(page);
3589 3590 3591 3592
	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);

3593
	hugetlb_count_add(pages_per_huge_page(h), mm);
3594
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3595
		/* Optimization, do the COW without a second fault */
3596
		ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
3597 3598
	}

3599
	spin_unlock(ptl);
A
Adam Litke 已提交
3600 3601
	unlock_page(page);
out:
3602
	return ret;
A
Adam Litke 已提交
3603 3604

backout:
3605
	spin_unlock(ptl);
3606
backout_unlocked:
A
Adam Litke 已提交
3607 3608 3609
	unlock_page(page);
	put_page(page);
	goto out;
3610 3611
}

3612
#ifdef CONFIG_SMP
3613
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637
			    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.
 */
3638
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3639 3640 3641 3642 3643 3644 3645 3646
			    struct vm_area_struct *vma,
			    struct address_space *mapping,
			    pgoff_t idx, unsigned long address)
{
	return 0;
}
#endif

3647
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3648
			unsigned long address, unsigned int flags)
3649
{
3650
	pte_t *ptep, entry;
3651
	spinlock_t *ptl;
3652
	int ret;
3653 3654
	u32 hash;
	pgoff_t idx;
3655
	struct page *page = NULL;
3656
	struct page *pagecache_page = NULL;
3657
	struct hstate *h = hstate_vma(vma);
3658
	struct address_space *mapping;
3659
	int need_wait_lock = 0;
3660

3661 3662
	address &= huge_page_mask(h);

3663 3664 3665
	ptep = huge_pte_offset(mm, address);
	if (ptep) {
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
3666
		if (unlikely(is_hugetlb_entry_migration(entry))) {
3667
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
3668 3669
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3670
			return VM_FAULT_HWPOISON_LARGE |
3671
				VM_FAULT_SET_HINDEX(hstate_index(h));
3672 3673 3674 3675
	} else {
		ptep = huge_pte_alloc(mm, address, huge_page_size(h));
		if (!ptep)
			return VM_FAULT_OOM;
3676 3677
	}

3678 3679 3680
	mapping = vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, vma, address);

3681 3682 3683 3684 3685
	/*
	 * 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.
	 */
3686 3687
	hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, address);
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
3688

3689 3690
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
3691
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3692
		goto out_mutex;
3693
	}
3694

N
Nick Piggin 已提交
3695
	ret = 0;
3696

3697 3698 3699 3700 3701 3702 3703 3704 3705 3706
	/*
	 * 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;

3707 3708 3709 3710 3711 3712 3713 3714
	/*
	 * 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.
	 */
3715
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3716 3717
		if (vma_needs_reservation(h, vma, address) < 0) {
			ret = VM_FAULT_OOM;
3718
			goto out_mutex;
3719
		}
3720
		/* Just decrements count, does not deallocate */
3721
		vma_end_reservation(h, vma, address);
3722

3723
		if (!(vma->vm_flags & VM_MAYSHARE))
3724 3725 3726 3727
			pagecache_page = hugetlbfs_pagecache_page(h,
								vma, address);
	}

3728 3729 3730 3731 3732 3733
	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;

3734 3735 3736 3737 3738 3739 3740
	/*
	 * 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)
3741 3742 3743 3744
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
3745

3746
	get_page(page);
3747

3748
	if (flags & FAULT_FLAG_WRITE) {
3749
		if (!huge_pte_write(entry)) {
3750
			ret = hugetlb_cow(mm, vma, address, ptep, entry,
3751
					pagecache_page, ptl);
3752
			goto out_put_page;
3753
		}
3754
		entry = huge_pte_mkdirty(entry);
3755 3756
	}
	entry = pte_mkyoung(entry);
3757 3758
	if (huge_ptep_set_access_flags(vma, address, ptep, entry,
						flags & FAULT_FLAG_WRITE))
3759
		update_mmu_cache(vma, address, ptep);
3760 3761 3762 3763
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
3764 3765
out_ptl:
	spin_unlock(ptl);
3766 3767 3768 3769 3770

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
3771
out_mutex:
3772
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
3773 3774 3775 3776 3777 3778 3779 3780 3781
	/*
	 * 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);
3782
	return ret;
3783 3784
}

3785 3786 3787 3788
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,
			 long i, unsigned int flags)
D
David Gibson 已提交
3789
{
3790 3791
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
3792
	unsigned long remainder = *nr_pages;
3793
	struct hstate *h = hstate_vma(vma);
D
David Gibson 已提交
3794 3795

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
3796
		pte_t *pte;
3797
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
3798
		int absent;
A
Adam Litke 已提交
3799
		struct page *page;
D
David Gibson 已提交
3800

3801 3802 3803 3804 3805 3806 3807 3808 3809
		/*
		 * 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
3810 3811
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
3812
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
3813
		 * first, for the page indexing below to work.
3814 3815
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
3816
		 */
3817
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3818 3819
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
3820 3821 3822 3823
		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
3824 3825 3826 3827
		 * 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
3828
		 */
H
Hugh Dickins 已提交
3829 3830
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3831 3832
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
3833 3834 3835
			remainder = 0;
			break;
		}
D
David Gibson 已提交
3836

3837 3838 3839 3840 3841 3842 3843 3844 3845 3846 3847
		/*
		 * 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)) ||
3848 3849
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
A
Adam Litke 已提交
3850
			int ret;
D
David Gibson 已提交
3851

3852 3853
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
3854 3855
			ret = hugetlb_fault(mm, vma, vaddr,
				(flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3856
			if (!(ret & VM_FAULT_ERROR))
A
Adam Litke 已提交
3857
				continue;
D
David Gibson 已提交
3858

A
Adam Litke 已提交
3859 3860 3861 3862
			remainder = 0;
			break;
		}

3863
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3864
		page = pte_page(huge_ptep_get(pte));
3865
same_page:
3866
		if (pages) {
H
Hugh Dickins 已提交
3867
			pages[i] = mem_map_offset(page, pfn_offset);
3868
			get_page_foll(pages[i]);
3869
		}
D
David Gibson 已提交
3870 3871 3872 3873 3874

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
3875
		++pfn_offset;
D
David Gibson 已提交
3876 3877
		--remainder;
		++i;
3878
		if (vaddr < vma->vm_end && remainder &&
3879
				pfn_offset < pages_per_huge_page(h)) {
3880 3881 3882 3883 3884 3885
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
3886
		spin_unlock(ptl);
D
David Gibson 已提交
3887
	}
3888
	*nr_pages = remainder;
D
David Gibson 已提交
3889 3890
	*position = vaddr;

H
Hugh Dickins 已提交
3891
	return i ? i : -EFAULT;
D
David Gibson 已提交
3892
}
3893

3894
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3895 3896 3897 3898 3899 3900
		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;
3901
	struct hstate *h = hstate_vma(vma);
3902
	unsigned long pages = 0;
3903 3904 3905 3906

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

3907
	mmu_notifier_invalidate_range_start(mm, start, end);
3908
	i_mmap_lock_write(vma->vm_file->f_mapping);
3909
	for (; address < end; address += huge_page_size(h)) {
3910
		spinlock_t *ptl;
3911 3912 3913
		ptep = huge_pte_offset(mm, address);
		if (!ptep)
			continue;
3914
		ptl = huge_pte_lock(h, mm, ptep);
3915 3916
		if (huge_pmd_unshare(mm, &address, ptep)) {
			pages++;
3917
			spin_unlock(ptl);
3918
			continue;
3919
		}
3920 3921 3922 3923 3924 3925 3926 3927 3928 3929 3930 3931 3932 3933 3934 3935 3936 3937 3938 3939
		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)) {
3940
			pte = huge_ptep_get_and_clear(mm, address, ptep);
3941
			pte = pte_mkhuge(huge_pte_modify(pte, newprot));
3942
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
3943
			set_huge_pte_at(mm, address, ptep, pte);
3944
			pages++;
3945
		}
3946
		spin_unlock(ptl);
3947
	}
3948
	/*
3949
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
3950
	 * may have cleared our pud entry and done put_page on the page table:
3951
	 * once we release i_mmap_rwsem, another task can do the final put_page
3952 3953
	 * and that page table be reused and filled with junk.
	 */
3954
	flush_tlb_range(vma, start, end);
3955
	mmu_notifier_invalidate_range(mm, start, end);
3956
	i_mmap_unlock_write(vma->vm_file->f_mapping);
3957
	mmu_notifier_invalidate_range_end(mm, start, end);
3958 3959

	return pages << h->order;
3960 3961
}

3962 3963
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
3964
					struct vm_area_struct *vma,
3965
					vm_flags_t vm_flags)
3966
{
3967
	long ret, chg;
3968
	struct hstate *h = hstate_inode(inode);
3969
	struct hugepage_subpool *spool = subpool_inode(inode);
3970
	struct resv_map *resv_map;
3971
	long gbl_reserve;
3972

3973 3974 3975
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
3976
	 * without using reserves
3977
	 */
3978
	if (vm_flags & VM_NORESERVE)
3979 3980
		return 0;

3981 3982 3983 3984 3985 3986
	/*
	 * 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
	 */
3987
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
3988
		resv_map = inode_resv_map(inode);
3989

3990
		chg = region_chg(resv_map, from, to);
3991 3992 3993

	} else {
		resv_map = resv_map_alloc();
3994 3995 3996
		if (!resv_map)
			return -ENOMEM;

3997
		chg = to - from;
3998

3999 4000 4001 4002
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

4003 4004 4005 4006
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
4007

4008 4009 4010 4011 4012 4013 4014
	/*
	 * 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) {
4015 4016 4017
		ret = -ENOSPC;
		goto out_err;
	}
4018 4019

	/*
4020
	 * Check enough hugepages are available for the reservation.
4021
	 * Hand the pages back to the subpool if there are not
4022
	 */
4023
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
4024
	if (ret < 0) {
4025 4026
		/* put back original number of pages, chg */
		(void)hugepage_subpool_put_pages(spool, chg);
4027
		goto out_err;
K
Ken Chen 已提交
4028
	}
4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039 4040

	/*
	 * 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
	 */
4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058
	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);
		}
	}
4059
	return 0;
4060
out_err:
4061 4062
	if (!vma || vma->vm_flags & VM_MAYSHARE)
		region_abort(resv_map, from, to);
J
Joonsoo Kim 已提交
4063 4064
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
4065
	return ret;
4066 4067
}

4068 4069
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
4070
{
4071
	struct hstate *h = hstate_inode(inode);
4072
	struct resv_map *resv_map = inode_resv_map(inode);
4073
	long chg = 0;
4074
	struct hugepage_subpool *spool = subpool_inode(inode);
4075
	long gbl_reserve;
K
Ken Chen 已提交
4076

4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087
	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
4088
	spin_lock(&inode->i_lock);
4089
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
4090 4091
	spin_unlock(&inode->i_lock);

4092 4093 4094 4095 4096 4097
	/*
	 * 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);
4098 4099

	return 0;
4100
}
4101

4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112
#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
4113 4114
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4115 4116 4117 4118 4119 4120 4121 4122 4123 4124 4125 4126 4127

	/*
	 * 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;
}

4128
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4129 4130 4131 4132 4133 4134 4135 4136 4137
{
	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)
4138 4139
		return true;
	return false;
4140 4141 4142 4143 4144 4145 4146
}

/*
 * 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
4147
 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160
 * 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;
4161
	spinlock_t *ptl;
4162 4163 4164 4165

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

4166
	i_mmap_lock_write(mapping);
4167 4168 4169 4170 4171 4172 4173 4174
	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) {
4175
				mm_inc_nr_pmds(mm);
4176 4177 4178 4179 4180 4181 4182 4183 4184
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

4185 4186
	ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
	spin_lock(ptl);
4187
	if (pud_none(*pud)) {
4188 4189
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
4190
	} else {
4191
		put_page(virt_to_page(spte));
4192 4193
		mm_inc_nr_pmds(mm);
	}
4194
	spin_unlock(ptl);
4195 4196
out:
	pte = (pte_t *)pmd_alloc(mm, pud, addr);
4197
	i_mmap_unlock_write(mapping);
4198 4199 4200 4201 4202 4203 4204 4205 4206 4207
	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.
 *
4208
 * called with page table lock held.
4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222 4223
 *
 * 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);
	pud_t *pud = pud_offset(pgd, *addr);

	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));
4224
	mm_dec_nr_pmds(mm);
4225 4226 4227
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
4228 4229 4230 4231 4232 4233
#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;
}
4234 4235 4236 4237 4238

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	return 0;
}
4239
#define want_pmd_share()	(0)
4240 4241
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
	pud = pud_alloc(mm, pgd, addr);
	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);
		}
	}
	BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));

	return pte;
}

pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd = NULL;

	pgd = pgd_offset(mm, addr);
	if (pgd_present(*pgd)) {
		pud = pud_offset(pgd, addr);
		if (pud_present(*pud)) {
			if (pud_huge(*pud))
				return (pte_t *)pud;
			pmd = pmd_offset(pud, addr);
		}
	}
	return (pte_t *) pmd;
}

4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299
#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
4300
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4301
		pmd_t *pmd, int flags)
4302
{
4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314
	struct page *page = NULL;
	spinlock_t *ptl;
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;
	if (pmd_present(*pmd)) {
4315
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4316 4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330
		if (flags & FOLL_GET)
			get_page(page);
	} else {
		if (is_hugetlb_entry_migration(huge_ptep_get((pte_t *)pmd))) {
			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);
4331 4332 4333
	return page;
}

4334
struct page * __weak
4335
follow_huge_pud(struct mm_struct *mm, unsigned long address,
4336
		pud_t *pud, int flags)
4337
{
4338 4339
	if (flags & FOLL_GET)
		return NULL;
4340

4341
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4342 4343
}

4344 4345
#ifdef CONFIG_MEMORY_FAILURE

4346 4347 4348 4349
/*
 * This function is called from memory failure code.
 * Assume the caller holds page lock of the head page.
 */
4350
int dequeue_hwpoisoned_huge_page(struct page *hpage)
4351 4352 4353
{
	struct hstate *h = page_hstate(hpage);
	int nid = page_to_nid(hpage);
4354
	int ret = -EBUSY;
4355 4356

	spin_lock(&hugetlb_lock);
4357 4358 4359 4360 4361
	/*
	 * 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)) {
4362 4363 4364 4365 4366 4367 4368
		/*
		 * 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);
4369
		set_page_refcounted(hpage);
4370 4371 4372 4373
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
		ret = 0;
	}
4374
	spin_unlock(&hugetlb_lock);
4375
	return ret;
4376
}
4377
#endif
4378 4379 4380

bool isolate_huge_page(struct page *page, struct list_head *list)
{
4381 4382
	bool ret = true;

4383
	VM_BUG_ON_PAGE(!PageHead(page), page);
4384
	spin_lock(&hugetlb_lock);
4385 4386 4387 4388 4389
	if (!page_huge_active(page) || !get_page_unless_zero(page)) {
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
4390
	list_move_tail(&page->lru, list);
4391
unlock:
4392
	spin_unlock(&hugetlb_lock);
4393
	return ret;
4394 4395 4396 4397
}

void putback_active_hugepage(struct page *page)
{
4398
	VM_BUG_ON_PAGE(!PageHead(page), page);
4399
	spin_lock(&hugetlb_lock);
4400
	set_page_huge_active(page);
4401 4402 4403 4404
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}