hugetlb.c 130.3 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/mmdebug.h>
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#include <linux/sched/signal.h>
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#include <linux/rmap.h>
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#include <linux/string_helpers.h>
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#include <linux/swap.h>
#include <linux/swapops.h>
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#include <linux/jhash.h>
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#include <asm/page.h>
#include <asm/pgtable.h>
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#include <asm/tlb.h>
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#include <linux/io.h>
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#include <linux/hugetlb.h>
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#include <linux/hugetlb_cgroup.h>
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#include <linux/node.h>
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#include <linux/userfaultfd_k.h>
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#include <linux/page_owner.h>
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#include "internal.h"
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int hugetlb_max_hstate __read_mostly;
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unsigned int default_hstate_idx;
struct hstate hstates[HUGE_MAX_HSTATE];
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/*
 * Minimum page order among possible hugepage sizes, set to a proper value
 * at boot time.
 */
static unsigned int minimum_order __read_mostly = UINT_MAX;
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__initdata LIST_HEAD(huge_boot_pages);

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/* for command line parsing */
static struct hstate * __initdata parsed_hstate;
static unsigned long __initdata default_hstate_max_huge_pages;
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static unsigned long __initdata default_hstate_size;
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static bool __initdata parsed_valid_hugepagesz = true;
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58
/*
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 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
 * free_huge_pages, and surplus_huge_pages.
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 */
62
DEFINE_SPINLOCK(hugetlb_lock);
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/*
 * Serializes faults on the same logical page.  This is used to
 * prevent spurious OOMs when the hugepage pool is fully utilized.
 */
static int num_fault_mutexes;
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struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
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/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);

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static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
{
	bool free = (spool->count == 0) && (spool->used_hpages == 0);

	spin_unlock(&spool->lock);

	/* If no pages are used, and no other handles to the subpool
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	 * remain, give up any reservations mased on minimum size and
	 * free the subpool */
	if (free) {
		if (spool->min_hpages != -1)
			hugetlb_acct_memory(spool->hstate,
						-spool->min_hpages);
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		kfree(spool);
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	}
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}

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

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

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

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

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

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

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

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

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/*
 * Subpool accounting for freeing and unreserving pages.
 * Return the number of global page reservations that must be dropped.
 * The return value may only be different than the passed value (delta)
 * in the case where a subpool minimum size must be maintained.
 */
static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
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				       long delta)
{
179 180
	long ret = delta;

181
	if (!spool)
182
		return delta;
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	spin_lock(&spool->lock);
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	if (spool->max_hpages != -1)		/* maximum size accounting */
		spool->used_hpages -= delta;

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

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

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

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

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

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

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/*
 * Add the huge page range represented by [f, t) to the reserve
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 * map.  In the normal case, existing regions will be expanded
 * to accommodate the specified range.  Sufficient regions should
 * exist for expansion due to the previous call to region_chg
 * with the same range.  However, it is possible that region_del
 * could have been called after region_chg and modifed the map
 * in such a way that no region exists to be expanded.  In this
 * case, pull a region descriptor from the cache associated with
 * the map and use that for the new range.
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 *
 * Return the number of new huge pages added to the map.  This
 * number is greater than or equal to zero.
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 */
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static long region_add(struct resv_map *resv, long f, long t)
260
{
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	struct list_head *head = &resv->regions;
262
	struct file_region *rg, *nrg, *trg;
263
	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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{
357
	struct list_head *head = &resv->regions;
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	struct file_region *rg, *nrg = NULL;
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	long chg = 0;

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

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

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

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

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

	/* If we are below the current region then a new region is required.
	 * Subtle, allocate a new region at the position but make it zero
	 * size such that we can guarantee to record the reservation. */
	if (&rg->link == head || t < rg->from) {
399
		if (!nrg) {
400
			resv->adds_in_progress--;
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			spin_unlock(&resv->lock);
			nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
			if (!nrg)
				return -ENOMEM;

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

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

	/* Check for and consume any regions we now overlap with. */
	list_for_each_entry(rg, rg->link.prev, link) {
		if (&rg->link == head)
			break;
		if (rg->from > t)
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			goto out;
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		/* We overlap with this area, if it extends further than
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		 * us then we must extend ourselves.  Account for its
		 * existing reservation. */
		if (rg->to > t) {
			chg += rg->to - t;
			t = rg->to;
		}
		chg -= rg->to - rg->from;
	}
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out:
	spin_unlock(&resv->lock);
	/*  We already know we raced and no longer need the new region */
	kfree(nrg);
	return chg;
out_nrg:
	spin_unlock(&resv->lock);
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	return chg;
}

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

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/*
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 * Delete the specified range [f, t) from the reserve map.  If the
 * t parameter is LONG_MAX, this indicates that ALL regions after f
 * should be deleted.  Locate the regions which intersect [f, t)
 * and either trim, delete or split the existing regions.
 *
 * Returns the number of huge pages deleted from the reserve map.
 * In the normal case, the return value is zero or more.  In the
 * case where a region must be split, a new region descriptor must
 * be allocated.  If the allocation fails, -ENOMEM will be returned.
 * NOTE: If the parameter t == LONG_MAX, then we will never split
 * a region and possibly return -ENOMEM.  Callers specifying
 * t == LONG_MAX do not need to check for -ENOMEM error.
481
 */
482
static long region_del(struct resv_map *resv, long f, long t)
483
{
484
	struct list_head *head = &resv->regions;
485
	struct file_region *rg, *trg;
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	struct file_region *nrg = NULL;
	long del = 0;
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489
retry:
490
	spin_lock(&resv->lock);
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	list_for_each_entry_safe(rg, trg, head, link) {
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		/*
		 * Skip regions before the range to be deleted.  file_region
		 * ranges are normally of the form [from, to).  However, there
		 * may be a "placeholder" entry in the map which is of the form
		 * (from, to) with from == to.  Check for placeholder entries
		 * at the beginning of the range to be deleted.
		 */
		if (rg->to <= f && (rg->to != rg->from || rg->to != f))
500
			continue;
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502
		if (rg->from >= t)
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			break;

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

			del += t - f;

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

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

			list_add(&nrg->link, &rg->link);
			nrg = NULL;
539
			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;
		}
556
	}
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	spin_unlock(&resv->lock);
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	kfree(nrg);
	return del;
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}

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

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

		hugetlb_acct_memory(h, 1);
	}
}

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

595
	spin_lock(&resv->lock);
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	/* Locate each segment we overlap with, and count that overlap. */
	list_for_each_entry(rg, head, link) {
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		long seg_from;
		long seg_to;
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		if (rg->to <= f)
			continue;
		if (rg->from >= t)
			break;

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

		chg += seg_to - seg_from;
	}
611
	spin_unlock(&resv->lock);
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	return chg;
}

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/*
 * Convert the address within this vma to the page offset within
 * the mapping, in pagecache page units; huge pages here.
 */
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static pgoff_t vma_hugecache_offset(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
622
{
623 624
	return ((address - vma->vm_start) >> huge_page_shift(h)) +
			(vma->vm_pgoff >> huge_page_order(h));
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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);
}
632
EXPORT_SYMBOL_GPL(linear_hugepage_index);
633

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/*
 * Return the size of the pages allocated when backing a VMA. In the majority
 * cases this will be same size as used by the page table entries.
 */
unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
{
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	if (vma->vm_ops && vma->vm_ops->pagesize)
		return vma->vm_ops->pagesize(vma);
	return PAGE_SIZE;
643
}
644
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
645

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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
649 650
 * architectures where it differs, an architecture-specific 'strong'
 * version of this symbol is required.
651
 */
652
__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
653 654 655 656
{
	return vma_kernel_pagesize(vma);
}

657 658 659 660 661 662 663
/*
 * 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)
664
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
665

666 667 668 669 670 671 672 673 674
/*
 * 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.
675 676 677 678 679 680 681 682 683
 *
 * 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.
684
 */
685 686 687 688 689 690 691 692 693 694 695
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;
}

696
struct resv_map *resv_map_alloc(void)
697 698
{
	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
699 700 701 702 703
	struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);

	if (!resv_map || !rg) {
		kfree(resv_map);
		kfree(rg);
704
		return NULL;
705
	}
706 707

	kref_init(&resv_map->refs);
708
	spin_lock_init(&resv_map->lock);
709 710
	INIT_LIST_HEAD(&resv_map->regions);

711 712 713 714 715 716
	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;

717 718 719
	return resv_map;
}

720
void resv_map_release(struct kref *ref)
721 722
{
	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
723 724
	struct list_head *head = &resv_map->region_cache;
	struct file_region *rg, *trg;
725 726

	/* Clear out any active regions before we release the map. */
727
	region_del(resv_map, 0, LONG_MAX);
728 729 730 731 732 733 734 735 736

	/* ... 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);

737 738 739
	kfree(resv_map);
}

740 741 742 743 744
static inline struct resv_map *inode_resv_map(struct inode *inode)
{
	return inode->i_mapping->private_data;
}

745
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
746
{
747
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
748 749 750 751 752 753 754
	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 {
755 756
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
757
	}
758 759
}

760
static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
761
{
762 763
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
764

765 766
	set_vma_private_data(vma, (get_vma_private_data(vma) &
				HPAGE_RESV_MASK) | (unsigned long)map);
767 768 769 770
}

static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
{
771 772
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
773 774

	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
775 776 777 778
}

static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
{
779
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
780 781

	return (get_vma_private_data(vma) & flag) != 0;
782 783
}

784
/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
785 786
void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
787
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
788
	if (!(vma->vm_flags & VM_MAYSHARE))
789 790 791 792
		vma->vm_private_data = (void *)0;
}

/* Returns true if the VMA has associated reserve pages */
793
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
794
{
795 796 797 798 799 800 801 802 803 804 805
	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)
806
			return true;
807
		else
808
			return false;
809
	}
810 811

	/* Shared mappings always use reserves */
812 813 814 815 816 817 818 819 820 821 822 823 824
	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;
	}
825 826 827 828 829

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
		/*
		 * Like the shared case above, a hole punch or truncate
		 * could have been performed on the private mapping.
		 * Examine the value of chg to determine if reserves
		 * actually exist or were previously consumed.
		 * Very Subtle - The value of chg comes from a previous
		 * call to vma_needs_reserves().  The reserve map for
		 * private mappings has different (opposite) semantics
		 * than that of shared mappings.  vma_needs_reserves()
		 * has already taken this difference in semantics into
		 * account.  Therefore, the meaning of chg is the same
		 * as in the shared case above.  Code could easily be
		 * combined, but keeping it separate draws attention to
		 * subtle differences.
		 */
		if (chg)
			return false;
		else
			return true;
	}
851

852
	return false;
853 854
}

855
static void enqueue_huge_page(struct hstate *h, struct page *page)
L
Linus Torvalds 已提交
856 857
{
	int nid = page_to_nid(page);
858
	list_move(&page->lru, &h->hugepage_freelists[nid]);
859 860
	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
L
Linus Torvalds 已提交
861 862
}

863
static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
864 865 866
{
	struct page *page;

867
	list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
868
		if (!PageHWPoison(page))
869 870 871 872 873 874
			break;
	/*
	 * if 'non-isolated free hugepage' not found on the list,
	 * the allocation fails.
	 */
	if (&h->hugepage_freelists[nid] == &page->lru)
875
		return NULL;
876
	list_move(&page->lru, &h->hugepage_activelist);
877
	set_page_refcounted(page);
878 879 880 881 882
	h->free_huge_pages--;
	h->free_huge_pages_node[nid]--;
	return page;
}

883 884
static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
		nodemask_t *nmask)
885
{
886 887 888 889 890
	unsigned int cpuset_mems_cookie;
	struct zonelist *zonelist;
	struct zone *zone;
	struct zoneref *z;
	int node = -1;
891

892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907
	zonelist = node_zonelist(nid, gfp_mask);

retry_cpuset:
	cpuset_mems_cookie = read_mems_allowed_begin();
	for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
		struct page *page;

		if (!cpuset_zone_allowed(zone, gfp_mask))
			continue;
		/*
		 * no need to ask again on the same node. Pool is node rather than
		 * zone aware
		 */
		if (zone_to_nid(zone) == node)
			continue;
		node = zone_to_nid(zone);
908 909 910 911 912

		page = dequeue_huge_page_node_exact(h, node);
		if (page)
			return page;
	}
913 914 915
	if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
		goto retry_cpuset;

916 917 918
	return NULL;
}

919 920 921
/* Movability of hugepages depends on migration support. */
static inline gfp_t htlb_alloc_mask(struct hstate *h)
{
922
	if (hugepage_migration_supported(h))
923 924 925 926 927
		return GFP_HIGHUSER_MOVABLE;
	else
		return GFP_HIGHUSER;
}

928 929
static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
930 931
				unsigned long address, int avoid_reserve,
				long chg)
L
Linus Torvalds 已提交
932
{
933
	struct page *page;
934
	struct mempolicy *mpol;
935
	gfp_t gfp_mask;
936
	nodemask_t *nodemask;
937
	int nid;
L
Linus Torvalds 已提交
938

939 940 941 942 943
	/*
	 * 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
	 */
944
	if (!vma_has_reserves(vma, chg) &&
945
			h->free_huge_pages - h->resv_huge_pages == 0)
946
		goto err;
947

948
	/* If reserves cannot be used, ensure enough pages are in the pool */
949
	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
950
		goto err;
951

952 953
	gfp_mask = htlb_alloc_mask(h);
	nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
954 955 956 957
	page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
	if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
		SetPagePrivate(page);
		h->resv_huge_pages--;
L
Linus Torvalds 已提交
958
	}
959

960
	mpol_cond_put(mpol);
L
Linus Torvalds 已提交
961
	return page;
962 963 964

err:
	return NULL;
L
Linus Torvalds 已提交
965 966
}

967 968 969 970 971 972 973 974 975
/*
 * 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)
{
976
	nid = next_node_in(nid, *nodes_allowed);
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 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037
	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--)

1038
#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1039
static void destroy_compound_gigantic_page(struct page *page,
1040
					unsigned int order)
1041 1042 1043 1044 1045
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

1046
	atomic_set(compound_mapcount_ptr(page), 0);
1047
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1048
		clear_compound_head(p);
1049 1050 1051 1052 1053 1054 1055
		set_page_refcounted(p);
	}

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

1056
static void free_gigantic_page(struct page *page, unsigned int order)
1057 1058 1059 1060 1061
{
	free_contig_range(page_to_pfn(page), 1 << order);
}

static int __alloc_gigantic_page(unsigned long start_pfn,
1062
				unsigned long nr_pages, gfp_t gfp_mask)
1063 1064
{
	unsigned long end_pfn = start_pfn + nr_pages;
1065
	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
1066
				  gfp_mask);
1067 1068
}

1069 1070
static bool pfn_range_valid_gigantic(struct zone *z,
			unsigned long start_pfn, unsigned long nr_pages)
1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
{
	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);

1081 1082 1083
		if (page_zone(page) != z)
			return false;

1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
		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);
}

1104 1105
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
		int nid, nodemask_t *nodemask)
1106
{
1107
	unsigned int order = huge_page_order(h);
1108 1109
	unsigned long nr_pages = 1 << order;
	unsigned long ret, pfn, flags;
1110 1111 1112
	struct zonelist *zonelist;
	struct zone *zone;
	struct zoneref *z;
1113

1114
	zonelist = node_zonelist(nid, gfp_mask);
1115
	for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nodemask) {
1116
		spin_lock_irqsave(&zone->lock, flags);
1117

1118 1119 1120
		pfn = ALIGN(zone->zone_start_pfn, nr_pages);
		while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
			if (pfn_range_valid_gigantic(zone, pfn, nr_pages)) {
1121 1122 1123 1124 1125 1126 1127
				/*
				 * 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...
				 */
1128 1129
				spin_unlock_irqrestore(&zone->lock, flags);
				ret = __alloc_gigantic_page(pfn, nr_pages, gfp_mask);
1130 1131
				if (!ret)
					return pfn_to_page(pfn);
1132
				spin_lock_irqsave(&zone->lock, flags);
1133 1134 1135 1136
			}
			pfn += nr_pages;
		}

1137
		spin_unlock_irqrestore(&zone->lock, flags);
1138 1139 1140 1141 1142 1143
	}

	return NULL;
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1144
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1145

1146
#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1147
static inline bool gigantic_page_supported(void) { return false; }
1148 1149
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
		int nid, nodemask_t *nodemask) { return NULL; }
1150
static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1151
static inline void destroy_compound_gigantic_page(struct page *page,
1152
						unsigned int order) { }
1153 1154
#endif

1155
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1156 1157
{
	int i;
1158

1159 1160
	if (hstate_is_gigantic(h) && !gigantic_page_supported())
		return;
1161

1162 1163 1164
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
1165 1166
		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
1167 1168
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1169
	}
1170
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1171
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1172
	set_page_refcounted(page);
1173 1174 1175 1176 1177 1178
	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
1179 1180
}

1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191
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;
}

1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216
/*
 * 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]);
}

1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238
/*
 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
 * code
 */
static inline bool PageHugeTemporary(struct page *page)
{
	if (!PageHuge(page))
		return false;

	return (unsigned long)page[2].mapping == -1U;
}

static inline void SetPageHugeTemporary(struct page *page)
{
	page[2].mapping = (void *)-1U;
}

static inline void ClearPageHugeTemporary(struct page *page)
{
	page[2].mapping = NULL;
}

1239
void free_huge_page(struct page *page)
1240
{
1241 1242 1243 1244
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1245
	struct hstate *h = page_hstate(page);
1246
	int nid = page_to_nid(page);
1247 1248
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1249
	bool restore_reserve;
1250

1251
	set_page_private(page, 0);
1252
	page->mapping = NULL;
1253 1254
	VM_BUG_ON_PAGE(page_count(page), page);
	VM_BUG_ON_PAGE(page_mapcount(page), page);
1255
	restore_reserve = PagePrivate(page);
1256
	ClearPagePrivate(page);
1257

1258 1259 1260 1261 1262 1263 1264 1265
	/*
	 * 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;

1266
	spin_lock(&hugetlb_lock);
1267
	clear_page_huge_active(page);
1268 1269
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1270 1271 1272
	if (restore_reserve)
		h->resv_huge_pages++;

1273 1274 1275 1276 1277
	if (PageHugeTemporary(page)) {
		list_del(&page->lru);
		ClearPageHugeTemporary(page);
		update_and_free_page(h, page);
	} else if (h->surplus_huge_pages_node[nid]) {
1278 1279
		/* remove the page from active list */
		list_del(&page->lru);
1280 1281 1282
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1283
	} else {
1284
		arch_clear_hugepage_flags(page);
1285
		enqueue_huge_page(h, page);
1286
	}
1287 1288 1289
	spin_unlock(&hugetlb_lock);
}

1290
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1291
{
1292
	INIT_LIST_HEAD(&page->lru);
1293
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1294
	spin_lock(&hugetlb_lock);
1295
	set_hugetlb_cgroup(page, NULL);
1296 1297
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1298 1299 1300
	spin_unlock(&hugetlb_lock);
}

1301
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1302 1303 1304 1305 1306 1307 1308
{
	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);
1309
	__ClearPageReserved(page);
1310
	__SetPageHead(page);
1311
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324
		/*
		 * 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);
1325
		set_page_count(p, 0);
1326
		set_compound_head(p, page);
1327
	}
1328
	atomic_set(compound_mapcount_ptr(page), -1);
1329 1330
}

A
Andrew Morton 已提交
1331 1332 1333 1334 1335
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1336 1337 1338 1339 1340 1341
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1342
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1343
}
1344 1345
EXPORT_SYMBOL_GPL(PageHuge);

1346 1347 1348 1349 1350 1351 1352 1353 1354
/*
 * 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;

1355
	return get_compound_page_dtor(page_head) == free_huge_page;
1356 1357
}

1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374
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;
}

1375
static struct page *alloc_buddy_huge_page(struct hstate *h,
1376
		gfp_t gfp_mask, int nid, nodemask_t *nmask)
L
Linus Torvalds 已提交
1377
{
1378
	int order = huge_page_order(h);
L
Linus Torvalds 已提交
1379
	struct page *page;
1380

1381 1382 1383 1384 1385 1386 1387 1388
	gfp_mask |= __GFP_COMP|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;
	if (nid == NUMA_NO_NODE)
		nid = numa_mem_id();
	page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask);
	if (page)
		__count_vm_event(HTLB_BUDDY_PGALLOC);
	else
		__count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1389 1390 1391 1392

	return page;
}

1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
/*
 * Common helper to allocate a fresh hugetlb page. All specific allocators
 * should use this function to get new hugetlb pages
 */
static struct page *alloc_fresh_huge_page(struct hstate *h,
		gfp_t gfp_mask, int nid, nodemask_t *nmask)
{
	struct page *page;

	if (hstate_is_gigantic(h))
		page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
	else
		page = alloc_buddy_huge_page(h, gfp_mask,
				nid, nmask);
	if (!page)
		return NULL;

	if (hstate_is_gigantic(h))
		prep_compound_gigantic_page(page, huge_page_order(h));
	prep_new_huge_page(h, page, page_to_nid(page));

	return page;
}

1417 1418 1419 1420
/*
 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
 * manner.
 */
1421
static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
1422 1423 1424
{
	struct page *page;
	int nr_nodes, node;
1425
	gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1426 1427

	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1428
		page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed);
1429
		if (page)
1430 1431 1432
			break;
	}

1433 1434
	if (!page)
		return 0;
1435

1436 1437 1438
	put_page(page); /* free it into the hugepage allocator */

	return 1;
1439 1440
}

1441 1442 1443 1444 1445 1446
/*
 * 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.
 */
1447 1448
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1449
{
1450
	int nr_nodes, node;
1451 1452
	int ret = 0;

1453
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1454 1455 1456 1457
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1458 1459
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1460
			struct page *page =
1461
				list_entry(h->hugepage_freelists[node].next,
1462 1463 1464
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1465
			h->free_huge_pages_node[node]--;
1466 1467
			if (acct_surplus) {
				h->surplus_huge_pages--;
1468
				h->surplus_huge_pages_node[node]--;
1469
			}
1470 1471
			update_and_free_page(h, page);
			ret = 1;
1472
			break;
1473
		}
1474
	}
1475 1476 1477 1478

	return ret;
}

1479 1480
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
1481 1482 1483
 * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
 * number of free hugepages would be reduced below the number of reserved
 * hugepages.
1484
 */
1485
int dissolve_free_huge_page(struct page *page)
1486
{
1487 1488
	int rc = 0;

1489 1490
	spin_lock(&hugetlb_lock);
	if (PageHuge(page) && !page_count(page)) {
1491 1492 1493
		struct page *head = compound_head(page);
		struct hstate *h = page_hstate(head);
		int nid = page_to_nid(head);
1494 1495 1496 1497
		if (h->free_huge_pages - h->resv_huge_pages == 0) {
			rc = -EBUSY;
			goto out;
		}
1498 1499 1500 1501 1502 1503 1504 1505
		/*
		 * Move PageHWPoison flag from head page to the raw error page,
		 * which makes any subpages rather than the error page reusable.
		 */
		if (PageHWPoison(head) && page != head) {
			SetPageHWPoison(page);
			ClearPageHWPoison(head);
		}
1506
		list_del(&head->lru);
1507 1508
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
1509
		h->max_huge_pages--;
1510
		update_and_free_page(h, head);
1511
	}
1512
out:
1513
	spin_unlock(&hugetlb_lock);
1514
	return rc;
1515 1516 1517 1518 1519
}

/*
 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 * make specified memory blocks removable from the system.
1520 1521
 * Note that this will dissolve a free gigantic hugepage completely, if any
 * part of it lies within the given range.
1522 1523
 * Also note that if dissolve_free_huge_page() returns with an error, all
 * free hugepages that were dissolved before that error are lost.
1524
 */
1525
int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1526 1527
{
	unsigned long pfn;
1528
	struct page *page;
1529
	int rc = 0;
1530

1531
	if (!hugepages_supported())
1532
		return rc;
1533

1534 1535 1536 1537 1538 1539 1540 1541
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
		page = pfn_to_page(pfn);
		if (PageHuge(page) && !page_count(page)) {
			rc = dissolve_free_huge_page(page);
			if (rc)
				break;
		}
	}
1542 1543

	return rc;
1544 1545
}

1546 1547 1548
/*
 * Allocates a fresh surplus page from the page allocator.
 */
1549
static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1550
		int nid, nodemask_t *nmask)
1551
{
1552
	struct page *page = NULL;
1553

1554
	if (hstate_is_gigantic(h))
1555 1556
		return NULL;

1557
	spin_lock(&hugetlb_lock);
1558 1559
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
		goto out_unlock;
1560 1561
	spin_unlock(&hugetlb_lock);

1562
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask);
1563
	if (!page)
1564
		return NULL;
1565 1566

	spin_lock(&hugetlb_lock);
1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579
	/*
	 * We could have raced with the pool size change.
	 * Double check that and simply deallocate the new page
	 * if we would end up overcommiting the surpluses. Abuse
	 * temporary page to workaround the nasty free_huge_page
	 * codeflow
	 */
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
		SetPageHugeTemporary(page);
		put_page(page);
		page = NULL;
	} else {
		h->surplus_huge_pages++;
1580
		h->surplus_huge_pages_node[page_to_nid(page)]++;
1581
	}
1582 1583

out_unlock:
1584
	spin_unlock(&hugetlb_lock);
1585 1586 1587 1588

	return page;
}

1589
static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1590 1591 1592 1593 1594 1595 1596
		int nid, nodemask_t *nmask)
{
	struct page *page;

	if (hstate_is_gigantic(h))
		return NULL;

1597
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask);
1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609
	if (!page)
		return NULL;

	/*
	 * We do not account these pages as surplus because they are only
	 * temporary and will be released properly on the last reference
	 */
	SetPageHugeTemporary(page);

	return page;
}

1610 1611 1612
/*
 * Use the VMA's mpolicy to allocate a huge page from the buddy.
 */
D
Dave Hansen 已提交
1613
static
1614
struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1615 1616
		struct vm_area_struct *vma, unsigned long addr)
{
1617 1618 1619 1620 1621 1622 1623
	struct page *page;
	struct mempolicy *mpol;
	gfp_t gfp_mask = htlb_alloc_mask(h);
	int nid;
	nodemask_t *nodemask;

	nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1624
	page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1625 1626 1627
	mpol_cond_put(mpol);

	return page;
1628 1629
}

1630
/* page migration callback function */
1631 1632
struct page *alloc_huge_page_node(struct hstate *h, int nid)
{
1633
	gfp_t gfp_mask = htlb_alloc_mask(h);
1634
	struct page *page = NULL;
1635

1636 1637 1638
	if (nid != NUMA_NO_NODE)
		gfp_mask |= __GFP_THISNODE;

1639
	spin_lock(&hugetlb_lock);
1640
	if (h->free_huge_pages - h->resv_huge_pages > 0)
1641
		page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL);
1642 1643
	spin_unlock(&hugetlb_lock);

1644
	if (!page)
1645
		page = alloc_migrate_huge_page(h, gfp_mask, nid, NULL);
1646 1647 1648 1649

	return page;
}

1650
/* page migration callback function */
1651 1652
struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
		nodemask_t *nmask)
1653
{
1654
	gfp_t gfp_mask = htlb_alloc_mask(h);
1655 1656 1657

	spin_lock(&hugetlb_lock);
	if (h->free_huge_pages - h->resv_huge_pages > 0) {
1658 1659 1660 1661 1662 1663
		struct page *page;

		page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
		if (page) {
			spin_unlock(&hugetlb_lock);
			return page;
1664 1665 1666 1667
		}
	}
	spin_unlock(&hugetlb_lock);

1668
	return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1669 1670
}

1671
/* mempolicy aware migration callback */
1672 1673
struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
		unsigned long address)
1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688
{
	struct mempolicy *mpol;
	nodemask_t *nodemask;
	struct page *page;
	gfp_t gfp_mask;
	int node;

	gfp_mask = htlb_alloc_mask(h);
	node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
	page = alloc_huge_page_nodemask(h, node, nodemask);
	mpol_cond_put(mpol);

	return page;
}

1689
/*
L
Lucas De Marchi 已提交
1690
 * Increase the hugetlb pool such that it can accommodate a reservation
1691 1692
 * of size 'delta'.
 */
1693
static int gather_surplus_pages(struct hstate *h, int delta)
1694 1695 1696 1697 1698
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
1699
	bool alloc_ok = true;
1700

1701
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1702
	if (needed <= 0) {
1703
		h->resv_huge_pages += delta;
1704
		return 0;
1705
	}
1706 1707 1708 1709 1710 1711 1712 1713

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
1714
		page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
1715
				NUMA_NO_NODE, NULL);
1716 1717 1718 1719
		if (!page) {
			alloc_ok = false;
			break;
		}
1720
		list_add(&page->lru, &surplus_list);
1721
		cond_resched();
1722
	}
1723
	allocated += i;
1724 1725 1726 1727 1728 1729

	/*
	 * 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);
1730 1731
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
1732 1733 1734 1735 1736 1737 1738 1739 1740 1741
	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;
	}
1742 1743
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
1744
	 * needed to accommodate the reservation.  Add the appropriate number
1745
	 * of pages to the hugetlb pool and free the extras back to the buddy
1746 1747 1748
	 * 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.
1749 1750
	 */
	needed += allocated;
1751
	h->resv_huge_pages += delta;
1752
	ret = 0;
1753

1754
	/* Free the needed pages to the hugetlb pool */
1755
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1756 1757
		if ((--needed) < 0)
			break;
1758 1759 1760 1761 1762
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
1763
		VM_BUG_ON_PAGE(page_count(page), page);
1764
		enqueue_huge_page(h, page);
1765
	}
1766
free:
1767
	spin_unlock(&hugetlb_lock);
1768 1769

	/* Free unnecessary surplus pages to the buddy allocator */
1770 1771
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
1772
	spin_lock(&hugetlb_lock);
1773 1774 1775 1776 1777

	return ret;
}

/*
1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789
 * This routine has two main purposes:
 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
 *    in unused_resv_pages.  This corresponds to the prior adjustments made
 *    to the associated reservation map.
 * 2) Free any unused surplus pages that may have been allocated to satisfy
 *    the reservation.  As many as unused_resv_pages may be freed.
 *
 * Called with hugetlb_lock held.  However, the lock could be dropped (and
 * reacquired) during calls to cond_resched_lock.  Whenever dropping the lock,
 * we must make sure nobody else can claim pages we are in the process of
 * freeing.  Do this by ensuring resv_huge_page always is greater than the
 * number of huge pages we plan to free when dropping the lock.
1790
 */
1791 1792
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
1793 1794 1795
{
	unsigned long nr_pages;

1796
	/* Cannot return gigantic pages currently */
1797
	if (hstate_is_gigantic(h))
1798
		goto out;
1799

1800 1801 1802 1803
	/*
	 * Part (or even all) of the reservation could have been backed
	 * by pre-allocated pages. Only free surplus pages.
	 */
1804
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1805

1806 1807
	/*
	 * We want to release as many surplus pages as possible, spread
1808 1809 1810 1811 1812
	 * 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.
1813 1814 1815 1816
	 *
	 * Note that we decrement resv_huge_pages as we free the pages.  If
	 * we drop the lock, resv_huge_pages will still be sufficiently large
	 * to cover subsequent pages we may free.
1817 1818
	 */
	while (nr_pages--) {
1819 1820
		h->resv_huge_pages--;
		unused_resv_pages--;
1821
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1822
			goto out;
1823
		cond_resched_lock(&hugetlb_lock);
1824
	}
1825 1826 1827 1828

out:
	/* Fully uncommit the reservation */
	h->resv_huge_pages -= unused_resv_pages;
1829 1830
}

1831

1832
/*
1833
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1834
 * are used by the huge page allocation routines to manage reservations.
1835 1836 1837 1838 1839 1840
 *
 * 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
1841 1842 1843
 * 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.
1844 1845 1846 1847 1848 1849
 *
 * 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.
1850 1851 1852 1853 1854
 *
 * vma_add_reservation is used in error paths where a reservation must
 * be restored when a newly allocated huge page must be freed.  It is
 * to be called after calling vma_needs_reservation to determine if a
 * reservation exists.
1855
 */
1856 1857 1858
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
1859
	VMA_END_RESV,
1860
	VMA_ADD_RESV,
1861
};
1862 1863
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
1864
				enum vma_resv_mode mode)
1865
{
1866 1867
	struct resv_map *resv;
	pgoff_t idx;
1868
	long ret;
1869

1870 1871
	resv = vma_resv_map(vma);
	if (!resv)
1872
		return 1;
1873

1874
	idx = vma_hugecache_offset(h, vma, addr);
1875 1876
	switch (mode) {
	case VMA_NEEDS_RESV:
1877
		ret = region_chg(resv, idx, idx + 1);
1878 1879 1880 1881
		break;
	case VMA_COMMIT_RESV:
		ret = region_add(resv, idx, idx + 1);
		break;
1882
	case VMA_END_RESV:
1883 1884 1885
		region_abort(resv, idx, idx + 1);
		ret = 0;
		break;
1886 1887 1888 1889 1890 1891 1892 1893
	case VMA_ADD_RESV:
		if (vma->vm_flags & VM_MAYSHARE)
			ret = region_add(resv, idx, idx + 1);
		else {
			region_abort(resv, idx, idx + 1);
			ret = region_del(resv, idx, idx + 1);
		}
		break;
1894 1895 1896
	default:
		BUG();
	}
1897

1898
	if (vma->vm_flags & VM_MAYSHARE)
1899
		return ret;
1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918
	else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
		/*
		 * In most cases, reserves always exist for private mappings.
		 * However, a file associated with mapping could have been
		 * hole punched or truncated after reserves were consumed.
		 * As subsequent fault on such a range will not use reserves.
		 * Subtle - The reserve map for private mappings has the
		 * opposite meaning than that of shared mappings.  If NO
		 * entry is in the reserve map, it means a reservation exists.
		 * If an entry exists in the reserve map, it means the
		 * reservation has already been consumed.  As a result, the
		 * return value of this routine is the opposite of the
		 * value returned from reserve map manipulation routines above.
		 */
		if (ret)
			return 0;
		else
			return 1;
	}
1919
	else
1920
		return ret < 0 ? ret : 0;
1921
}
1922 1923

static long vma_needs_reservation(struct hstate *h,
1924
			struct vm_area_struct *vma, unsigned long addr)
1925
{
1926
	return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
1927
}
1928

1929 1930 1931
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
1932 1933 1934
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

1935
static void vma_end_reservation(struct hstate *h,
1936 1937
			struct vm_area_struct *vma, unsigned long addr)
{
1938
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
1939 1940
}

1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990
static long vma_add_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
	return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
}

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

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

1991
struct page *alloc_huge_page(struct vm_area_struct *vma,
1992
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
1993
{
1994
	struct hugepage_subpool *spool = subpool_vma(vma);
1995
	struct hstate *h = hstate_vma(vma);
1996
	struct page *page;
1997 1998
	long map_chg, map_commit;
	long gbl_chg;
1999 2000
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
2001

2002
	idx = hstate_index(h);
2003
	/*
2004 2005 2006
	 * 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).
2007
	 */
2008 2009
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
2010
		return ERR_PTR(-ENOMEM);
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

	/*
	 * 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) {
2022
			vma_end_reservation(h, vma, addr);
2023
			return ERR_PTR(-ENOSPC);
2024
		}
L
Linus Torvalds 已提交
2025

2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037
		/*
		 * 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;
	}

2038
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2039 2040 2041
	if (ret)
		goto out_subpool_put;

L
Linus Torvalds 已提交
2042
	spin_lock(&hugetlb_lock);
2043 2044 2045 2046 2047 2048
	/*
	 * 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);
2049
	if (!page) {
2050
		spin_unlock(&hugetlb_lock);
2051
		page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2052 2053
		if (!page)
			goto out_uncharge_cgroup;
2054 2055 2056 2057
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
2058 2059
		spin_lock(&hugetlb_lock);
		list_move(&page->lru, &h->hugepage_activelist);
2060
		/* Fall through */
K
Ken Chen 已提交
2061
	}
2062 2063
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
	spin_unlock(&hugetlb_lock);
2064

2065
	set_page_private(page, (unsigned long)spool);
2066

2067 2068
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082
		/*
		 * 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);
	}
2083
	return page;
2084 2085 2086 2087

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
out_subpool_put:
2088
	if (map_chg || avoid_reserve)
2089
		hugepage_subpool_put_pages(spool, 1);
2090
	vma_end_reservation(h, vma, addr);
2091
	return ERR_PTR(-ENOSPC);
2092 2093
}

2094 2095 2096
int alloc_bootmem_huge_page(struct hstate *h)
	__attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
int __alloc_bootmem_huge_page(struct hstate *h)
2097 2098
{
	struct huge_bootmem_page *m;
2099
	int nr_nodes, node;
2100

2101
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2102 2103
		void *addr;

2104 2105 2106
		addr = memblock_virt_alloc_try_nid_nopanic(
				huge_page_size(h), huge_page_size(h),
				0, BOOTMEM_ALLOC_ACCESSIBLE, node);
2107 2108 2109 2110 2111 2112 2113
		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;
2114
			goto found;
2115 2116 2117 2118 2119
		}
	}
	return 0;

found:
2120
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2121 2122 2123 2124 2125 2126
	/* 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;
}

2127 2128
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
2129 2130 2131 2132 2133 2134 2135
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

2136 2137 2138 2139 2140 2141 2142
/* 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;
2143 2144 2145 2146
		struct page *page;

#ifdef CONFIG_HIGHMEM
		page = pfn_to_page(m->phys >> PAGE_SHIFT);
2147 2148
		memblock_free_late(__pa(m),
				   sizeof(struct huge_bootmem_page));
2149 2150 2151
#else
		page = virt_to_page(m);
#endif
2152
		WARN_ON(page_count(page) != 1);
2153
		prep_compound_huge_page(page, h->order);
2154
		WARN_ON(PageReserved(page));
2155
		prep_new_huge_page(h, page, page_to_nid(page));
2156 2157
		put_page(page); /* free it into the hugepage allocator */

2158 2159 2160 2161 2162 2163
		/*
		 * 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.
		 */
2164
		if (hstate_is_gigantic(h))
2165
			adjust_managed_page_count(page, 1 << h->order);
2166
		cond_resched();
2167 2168 2169
	}
}

2170
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2171 2172
{
	unsigned long i;
2173

2174
	for (i = 0; i < h->max_huge_pages; ++i) {
2175
		if (hstate_is_gigantic(h)) {
2176 2177
			if (!alloc_bootmem_huge_page(h))
				break;
2178
		} else if (!alloc_pool_huge_page(h,
2179
					 &node_states[N_MEMORY]))
L
Linus Torvalds 已提交
2180
			break;
2181
		cond_resched();
L
Linus Torvalds 已提交
2182
	}
2183 2184 2185
	if (i < h->max_huge_pages) {
		char buf[32];

2186
		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2187 2188 2189 2190
		pr_warn("HugeTLB: allocating %lu of page size %s failed.  Only allocated %lu hugepages.\n",
			h->max_huge_pages, buf, i);
		h->max_huge_pages = i;
	}
2191 2192 2193 2194 2195 2196 2197
}

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

	for_each_hstate(h) {
2198 2199 2200
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2201
		/* oversize hugepages were init'ed in early boot */
2202
		if (!hstate_is_gigantic(h))
2203
			hugetlb_hstate_alloc_pages(h);
2204
	}
2205
	VM_BUG_ON(minimum_order == UINT_MAX);
2206 2207 2208 2209 2210 2211 2212
}

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

	for_each_hstate(h) {
A
Andi Kleen 已提交
2213
		char buf[32];
2214 2215

		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2216
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2217
			buf, h->free_huge_pages);
2218 2219 2220
	}
}

L
Linus Torvalds 已提交
2221
#ifdef CONFIG_HIGHMEM
2222 2223
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2224
{
2225 2226
	int i;

2227
	if (hstate_is_gigantic(h))
2228 2229
		return;

2230
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2231
		struct page *page, *next;
2232 2233 2234
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2235
				return;
L
Linus Torvalds 已提交
2236 2237 2238
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2239
			update_and_free_page(h, page);
2240 2241
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2242 2243 2244 2245
		}
	}
}
#else
2246 2247
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2248 2249 2250 2251
{
}
#endif

2252 2253 2254 2255 2256
/*
 * 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.
 */
2257 2258
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2259
{
2260
	int nr_nodes, node;
2261 2262 2263

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

2264 2265 2266 2267
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2268
		}
2269 2270 2271 2272 2273
	} 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;
2274
		}
2275 2276
	}
	return 0;
2277

2278 2279 2280 2281
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2282 2283
}

2284
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2285 2286
static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2287
{
2288
	unsigned long min_count, ret;
L
Linus Torvalds 已提交
2289

2290
	if (hstate_is_gigantic(h) && !gigantic_page_supported())
2291 2292
		return h->max_huge_pages;

2293 2294 2295 2296
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2297
	 *
2298
	 * We might race with alloc_surplus_huge_page() here and be unable
2299 2300 2301 2302
	 * 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.
2303
	 */
L
Linus Torvalds 已提交
2304
	spin_lock(&hugetlb_lock);
2305
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2306
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2307 2308 2309
			break;
	}

2310
	while (count > persistent_huge_pages(h)) {
2311 2312 2313 2314 2315 2316
		/*
		 * 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);
2317 2318 2319 2320

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

2321
		ret = alloc_pool_huge_page(h, nodes_allowed);
2322 2323 2324 2325
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2326 2327 2328
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2329 2330 2331 2332 2333 2334 2335 2336
	}

	/*
	 * 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.
2337 2338 2339 2340
	 *
	 * 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
2341
	 * alloc_surplus_huge_page() is checking the global counter,
2342 2343 2344
	 * 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.
2345
	 */
2346
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2347
	min_count = max(count, min_count);
2348
	try_to_free_low(h, min_count, nodes_allowed);
2349
	while (min_count < persistent_huge_pages(h)) {
2350
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2351
			break;
2352
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2353
	}
2354
	while (count < persistent_huge_pages(h)) {
2355
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2356 2357 2358
			break;
	}
out:
2359
	ret = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2360
	spin_unlock(&hugetlb_lock);
2361
	return ret;
L
Linus Torvalds 已提交
2362 2363
}

2364 2365 2366 2367 2368 2369 2370 2371 2372 2373
#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];

2374 2375 2376
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2377 2378
{
	int i;
2379

2380
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2381 2382 2383
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2384
			return &hstates[i];
2385 2386 2387
		}

	return kobj_to_node_hstate(kobj, nidp);
2388 2389
}

2390
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2391 2392
					struct kobj_attribute *attr, char *buf)
{
2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403
	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);
2404
}
2405

2406 2407 2408
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2409 2410
{
	int err;
2411
	NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
2412

2413
	if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
2414 2415 2416 2417
		err = -EINVAL;
		goto out;
	}

2418 2419 2420 2421 2422 2423 2424
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
				init_nodemask_of_mempolicy(nodes_allowed))) {
			NODEMASK_FREE(nodes_allowed);
2425
			nodes_allowed = &node_states[N_MEMORY];
2426 2427 2428 2429 2430 2431 2432 2433 2434
		}
	} 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
2435
		nodes_allowed = &node_states[N_MEMORY];
2436

2437
	h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
2438

2439
	if (nodes_allowed != &node_states[N_MEMORY])
2440 2441 2442
		NODEMASK_FREE(nodes_allowed);

	return len;
2443 2444 2445
out:
	NODEMASK_FREE(nodes_allowed);
	return err;
2446 2447
}

2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464
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);
}

2465 2466 2467 2468 2469 2470 2471 2472 2473
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)
{
2474
	return nr_hugepages_store_common(false, kobj, buf, len);
2475 2476 2477
}
HSTATE_ATTR(nr_hugepages);

2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492
#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)
{
2493
	return nr_hugepages_store_common(true, kobj, buf, len);
2494 2495 2496 2497 2498
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2499 2500 2501
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2502
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2503 2504
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2505

2506 2507 2508 2509 2510
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;
2511
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2512

2513
	if (hstate_is_gigantic(h))
2514 2515
		return -EINVAL;

2516
	err = kstrtoul(buf, 10, &input);
2517
	if (err)
2518
		return err;
2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530

	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)
{
2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541
	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);
2542 2543 2544 2545 2546 2547
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2548
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2549 2550 2551 2552 2553 2554 2555
	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)
{
2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566
	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);
2567 2568 2569 2570 2571 2572 2573 2574 2575
}
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,
2576 2577 2578
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
2579 2580 2581
	NULL,
};

2582
static const struct attribute_group hstate_attr_group = {
2583 2584 2585
	.attrs = hstate_attrs,
};

J
Jeff Mahoney 已提交
2586 2587
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
2588
				    const struct attribute_group *hstate_attr_group)
2589 2590
{
	int retval;
2591
	int hi = hstate_index(h);
2592

2593 2594
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
2595 2596
		return -ENOMEM;

2597
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2598
	if (retval)
2599
		kobject_put(hstate_kobjs[hi]);
2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613

	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) {
2614 2615
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
2616
		if (err)
2617
			pr_err("Hugetlb: Unable to add hstate %s", h->name);
2618 2619 2620
	}
}

2621 2622 2623 2624
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2625 2626 2627
 * 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
2628 2629 2630 2631 2632 2633
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
2634
static struct node_hstate node_hstates[MAX_NUMNODES];
2635 2636

/*
2637
 * A subset of global hstate attributes for node devices
2638 2639 2640 2641 2642 2643 2644 2645
 */
static struct attribute *per_node_hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
	NULL,
};

2646
static const struct attribute_group per_node_hstate_attr_group = {
2647 2648 2649 2650
	.attrs = per_node_hstate_attrs,
};

/*
2651
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673
 * 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;
}

/*
2674
 * Unregister hstate attributes from a single node device.
2675 2676
 * No-op if no hstate attributes attached.
 */
2677
static void hugetlb_unregister_node(struct node *node)
2678 2679
{
	struct hstate *h;
2680
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2681 2682

	if (!nhs->hugepages_kobj)
2683
		return;		/* no hstate attributes */
2684

2685 2686 2687 2688 2689
	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;
2690
		}
2691
	}
2692 2693 2694 2695 2696 2697 2698

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


/*
2699
 * Register hstate attributes for a single node device.
2700 2701
 * No-op if attributes already registered.
 */
2702
static void hugetlb_register_node(struct node *node)
2703 2704
{
	struct hstate *h;
2705
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2706 2707 2708 2709 2710 2711
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2712
							&node->dev.kobj);
2713 2714 2715 2716 2717 2718 2719 2720
	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) {
2721 2722
			pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
				h->name, node->dev.id);
2723 2724 2725 2726 2727 2728 2729
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
2730
 * hugetlb init time:  register hstate attributes for all registered node
2731 2732
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
2733
 */
2734
static void __init hugetlb_register_all_nodes(void)
2735 2736 2737
{
	int nid;

2738
	for_each_node_state(nid, N_MEMORY) {
2739
		struct node *node = node_devices[nid];
2740
		if (node->dev.id == nid)
2741 2742 2743 2744
			hugetlb_register_node(node);
	}

	/*
2745
	 * Let the node device driver know we're here so it can
2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764
	 * [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

2765 2766
static int __init hugetlb_init(void)
{
2767 2768
	int i;

2769
	if (!hugepages_supported())
2770
		return 0;
2771

2772
	if (!size_to_hstate(default_hstate_size)) {
2773 2774 2775 2776 2777
		if (default_hstate_size != 0) {
			pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
			       default_hstate_size, HPAGE_SIZE);
		}

2778 2779 2780
		default_hstate_size = HPAGE_SIZE;
		if (!size_to_hstate(default_hstate_size))
			hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
2781
	}
2782
	default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2783 2784 2785 2786
	if (default_hstate_max_huge_pages) {
		if (!default_hstate.max_huge_pages)
			default_hstate.max_huge_pages = default_hstate_max_huge_pages;
	}
2787 2788

	hugetlb_init_hstates();
2789
	gather_bootmem_prealloc();
2790 2791 2792
	report_hugepages();

	hugetlb_sysfs_init();
2793
	hugetlb_register_all_nodes();
2794
	hugetlb_cgroup_file_init();
2795

2796 2797 2798 2799 2800
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
2801
	hugetlb_fault_mutex_table =
2802 2803
		kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
			      GFP_KERNEL);
2804
	BUG_ON(!hugetlb_fault_mutex_table);
2805 2806

	for (i = 0; i < num_fault_mutexes; i++)
2807
		mutex_init(&hugetlb_fault_mutex_table[i]);
2808 2809
	return 0;
}
2810
subsys_initcall(hugetlb_init);
2811 2812

/* Should be called on processing a hugepagesz=... option */
2813 2814 2815 2816 2817
void __init hugetlb_bad_size(void)
{
	parsed_valid_hugepagesz = false;
}

2818
void __init hugetlb_add_hstate(unsigned int order)
2819 2820
{
	struct hstate *h;
2821 2822
	unsigned long i;

2823
	if (size_to_hstate(PAGE_SIZE << order)) {
J
Joe Perches 已提交
2824
		pr_warn("hugepagesz= specified twice, ignoring\n");
2825 2826
		return;
	}
2827
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2828
	BUG_ON(order == 0);
2829
	h = &hstates[hugetlb_max_hstate++];
2830 2831
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2832 2833 2834 2835
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2836
	INIT_LIST_HEAD(&h->hugepage_activelist);
2837 2838
	h->next_nid_to_alloc = first_memory_node;
	h->next_nid_to_free = first_memory_node;
2839 2840
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
2841

2842 2843 2844
	parsed_hstate = h;
}

2845
static int __init hugetlb_nrpages_setup(char *s)
2846 2847
{
	unsigned long *mhp;
2848
	static unsigned long *last_mhp;
2849

2850 2851 2852 2853 2854 2855
	if (!parsed_valid_hugepagesz) {
		pr_warn("hugepages = %s preceded by "
			"an unsupported hugepagesz, ignoring\n", s);
		parsed_valid_hugepagesz = true;
		return 1;
	}
2856
	/*
2857
	 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2858 2859
	 * so this hugepages= parameter goes to the "default hstate".
	 */
2860
	else if (!hugetlb_max_hstate)
2861 2862 2863 2864
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

2865
	if (mhp == last_mhp) {
J
Joe Perches 已提交
2866
		pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2867 2868 2869
		return 1;
	}

2870 2871 2872
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

2873 2874 2875 2876 2877
	/*
	 * 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.
	 */
2878
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2879 2880 2881 2882
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

2883 2884
	return 1;
}
2885 2886 2887 2888 2889 2890 2891 2892
__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);
2893

2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905
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
2906 2907 2908
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
2909
{
2910
	struct hstate *h = &default_hstate;
2911
	unsigned long tmp = h->max_huge_pages;
2912
	int ret;
2913

2914
	if (!hugepages_supported())
2915
		return -EOPNOTSUPP;
2916

2917 2918
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2919 2920 2921
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2922

2923 2924 2925
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
2926 2927
out:
	return ret;
L
Linus Torvalds 已提交
2928
}
2929

2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946
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 */

2947
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2948
			void __user *buffer,
2949 2950
			size_t *length, loff_t *ppos)
{
2951
	struct hstate *h = &default_hstate;
2952
	unsigned long tmp;
2953
	int ret;
2954

2955
	if (!hugepages_supported())
2956
		return -EOPNOTSUPP;
2957

2958
	tmp = h->nr_overcommit_huge_pages;
2959

2960
	if (write && hstate_is_gigantic(h))
2961 2962
		return -EINVAL;

2963 2964
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2965 2966 2967
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2968 2969 2970 2971 2972 2973

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
2974 2975
out:
	return ret;
2976 2977
}

L
Linus Torvalds 已提交
2978 2979
#endif /* CONFIG_SYSCTL */

2980
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
2981
{
2982 2983 2984
	struct hstate *h;
	unsigned long total = 0;

2985 2986
	if (!hugepages_supported())
		return;
2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007

	for_each_hstate(h) {
		unsigned long count = h->nr_huge_pages;

		total += (PAGE_SIZE << huge_page_order(h)) * count;

		if (h == &default_hstate)
			seq_printf(m,
				   "HugePages_Total:   %5lu\n"
				   "HugePages_Free:    %5lu\n"
				   "HugePages_Rsvd:    %5lu\n"
				   "HugePages_Surp:    %5lu\n"
				   "Hugepagesize:   %8lu kB\n",
				   count,
				   h->free_huge_pages,
				   h->resv_huge_pages,
				   h->surplus_huge_pages,
				   (PAGE_SIZE << huge_page_order(h)) / 1024);
	}

	seq_printf(m, "Hugetlb:        %8lu kB\n", total / 1024);
L
Linus Torvalds 已提交
3008 3009 3010 3011
}

int hugetlb_report_node_meminfo(int nid, char *buf)
{
3012
	struct hstate *h = &default_hstate;
3013 3014
	if (!hugepages_supported())
		return 0;
L
Linus Torvalds 已提交
3015 3016
	return sprintf(buf,
		"Node %d HugePages_Total: %5u\n"
3017 3018
		"Node %d HugePages_Free:  %5u\n"
		"Node %d HugePages_Surp:  %5u\n",
3019 3020 3021
		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
3022 3023
}

3024 3025 3026 3027 3028
void hugetlb_show_meminfo(void)
{
	struct hstate *h;
	int nid;

3029 3030 3031
	if (!hugepages_supported())
		return;

3032 3033 3034 3035 3036 3037 3038 3039 3040 3041
	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));
}

3042 3043 3044 3045 3046 3047
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
3048 3049 3050
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
3051 3052 3053 3054 3055 3056
	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
3057 3058
}

3059
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081
{
	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) {
3082
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
3083 3084
			goto out;

3085 3086
		if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
3087 3088 3089 3090 3091 3092
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
3093
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
3094 3095 3096 3097 3098 3099

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

3100 3101
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
3102
	struct resv_map *resv = vma_resv_map(vma);
3103 3104 3105 3106 3107

	/*
	 * 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
3108
	 * has a reference to the reservation map it cannot disappear until
3109 3110 3111
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
3112
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3113
		kref_get(&resv->refs);
3114 3115
}

3116 3117
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
3118
	struct hstate *h = hstate_vma(vma);
3119
	struct resv_map *resv = vma_resv_map(vma);
3120
	struct hugepage_subpool *spool = subpool_vma(vma);
3121
	unsigned long reserve, start, end;
3122
	long gbl_reserve;
3123

3124 3125
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
3126

3127 3128
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
3129

3130
	reserve = (end - start) - region_count(resv, start, end);
3131

3132 3133 3134
	kref_put(&resv->refs, resv_map_release);

	if (reserve) {
3135 3136 3137 3138 3139 3140
		/*
		 * 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);
3141
	}
3142 3143
}

3144 3145 3146 3147 3148 3149 3150
static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
{
	if (addr & ~(huge_page_mask(hstate_vma(vma))))
		return -EINVAL;
	return 0;
}

3151 3152 3153 3154 3155 3156 3157
static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
{
	struct hstate *hstate = hstate_vma(vma);

	return 1UL << huge_page_shift(hstate);
}

L
Linus Torvalds 已提交
3158 3159 3160 3161 3162 3163
/*
 * 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.
 */
3164
static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
L
Linus Torvalds 已提交
3165 3166
{
	BUG();
N
Nick Piggin 已提交
3167
	return 0;
L
Linus Torvalds 已提交
3168 3169
}

3170 3171 3172 3173 3174 3175 3176
/*
 * When a new function is introduced to vm_operations_struct and added
 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
 * This is because under System V memory model, mappings created via
 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
 * their original vm_ops are overwritten with shm_vm_ops.
 */
3177
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
3178
	.fault = hugetlb_vm_op_fault,
3179
	.open = hugetlb_vm_op_open,
3180
	.close = hugetlb_vm_op_close,
3181
	.split = hugetlb_vm_op_split,
3182
	.pagesize = hugetlb_vm_op_pagesize,
L
Linus Torvalds 已提交
3183 3184
};

3185 3186
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
3187 3188 3189
{
	pte_t entry;

3190
	if (writable) {
3191 3192
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
3193
	} else {
3194 3195
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
3196 3197 3198
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3199
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3200 3201 3202 3203

	return entry;
}

3204 3205 3206 3207 3208
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3209
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3210
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3211
		update_mmu_cache(vma, address, ptep);
3212 3213
}

3214
bool is_hugetlb_entry_migration(pte_t pte)
3215 3216 3217 3218
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3219
		return false;
3220 3221
	swp = pte_to_swp_entry(pte);
	if (non_swap_entry(swp) && is_migration_entry(swp))
3222
		return true;
3223
	else
3224
		return false;
3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238
}

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;
}
3239

D
David Gibson 已提交
3240 3241 3242 3243 3244
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;
3245
	unsigned long addr;
3246
	int cow;
3247 3248
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3249 3250 3251
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
	int ret = 0;
3252 3253

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3254

3255 3256 3257 3258 3259
	mmun_start = vma->vm_start;
	mmun_end = vma->vm_end;
	if (cow)
		mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);

3260
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3261
		spinlock_t *src_ptl, *dst_ptl;
3262
		src_pte = huge_pte_offset(src, addr, sz);
H
Hugh Dickins 已提交
3263 3264
		if (!src_pte)
			continue;
3265
		dst_pte = huge_pte_alloc(dst, addr, sz);
3266 3267 3268 3269
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3270 3271 3272 3273 3274

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

3275 3276 3277
		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);
3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291
		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);
3292 3293
				set_huge_swap_pte_at(src, addr, src_pte,
						     entry, sz);
3294
			}
3295
			set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3296
		} else {
3297
			if (cow) {
3298 3299 3300 3301 3302
				/*
				 * No need to notify as we are downgrading page
				 * table protection not changing it to point
				 * to a new page.
				 *
3303
				 * See Documentation/vm/mmu_notifier.rst
3304
				 */
3305
				huge_ptep_set_wrprotect(src, addr, src_pte);
3306
			}
3307
			entry = huge_ptep_get(src_pte);
3308 3309
			ptepage = pte_page(entry);
			get_page(ptepage);
3310
			page_dup_rmap(ptepage, true);
3311
			set_huge_pte_at(dst, addr, dst_pte, entry);
3312
			hugetlb_count_add(pages_per_huge_page(h), dst);
3313
		}
3314 3315
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3316 3317
	}

3318 3319 3320 3321
	if (cow)
		mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);

	return ret;
D
David Gibson 已提交
3322 3323
}

3324 3325 3326
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
3327 3328 3329
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3330
	pte_t *ptep;
D
David Gibson 已提交
3331
	pte_t pte;
3332
	spinlock_t *ptl;
D
David Gibson 已提交
3333
	struct page *page;
3334 3335
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3336 3337
	const unsigned long mmun_start = start;	/* For mmu_notifiers */
	const unsigned long mmun_end   = end;	/* For mmu_notifiers */
3338

D
David Gibson 已提交
3339
	WARN_ON(!is_vm_hugetlb_page(vma));
3340 3341
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3342

3343 3344 3345 3346 3347
	/*
	 * This is a hugetlb vma, all the pte entries should point
	 * to huge page.
	 */
	tlb_remove_check_page_size_change(tlb, sz);
3348
	tlb_start_vma(tlb, vma);
3349
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3350 3351
	address = start;
	for (; address < end; address += sz) {
3352
		ptep = huge_pte_offset(mm, address, sz);
A
Adam Litke 已提交
3353
		if (!ptep)
3354 3355
			continue;

3356
		ptl = huge_pte_lock(h, mm, ptep);
3357 3358 3359 3360
		if (huge_pmd_unshare(mm, &address, ptep)) {
			spin_unlock(ptl);
			continue;
		}
3361

3362
		pte = huge_ptep_get(ptep);
3363 3364 3365 3366
		if (huge_pte_none(pte)) {
			spin_unlock(ptl);
			continue;
		}
3367 3368

		/*
3369 3370
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3371
		 */
3372
		if (unlikely(!pte_present(pte))) {
3373
			huge_pte_clear(mm, address, ptep, sz);
3374 3375
			spin_unlock(ptl);
			continue;
3376
		}
3377 3378

		page = pte_page(pte);
3379 3380 3381 3382 3383 3384
		/*
		 * 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) {
3385 3386 3387 3388
			if (page != ref_page) {
				spin_unlock(ptl);
				continue;
			}
3389 3390 3391 3392 3393 3394 3395 3396
			/*
			 * 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);
		}

3397
		pte = huge_ptep_get_and_clear(mm, address, ptep);
3398
		tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3399
		if (huge_pte_dirty(pte))
3400
			set_page_dirty(page);
3401

3402
		hugetlb_count_sub(pages_per_huge_page(h), mm);
3403
		page_remove_rmap(page, true);
3404

3405
		spin_unlock(ptl);
3406
		tlb_remove_page_size(tlb, page, huge_page_size(h));
3407 3408 3409 3410 3411
		/*
		 * Bail out after unmapping reference page if supplied
		 */
		if (ref_page)
			break;
3412
	}
3413
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3414
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
3415
}
D
David Gibson 已提交
3416

3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428
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
3429
	 * is to clear it before releasing the i_mmap_rwsem. This works
3430
	 * because in the context this is called, the VMA is about to be
3431
	 * destroyed and the i_mmap_rwsem is held.
3432 3433 3434 3435
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

3436
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3437
			  unsigned long end, struct page *ref_page)
3438
{
3439 3440 3441 3442 3443
	struct mm_struct *mm;
	struct mmu_gather tlb;

	mm = vma->vm_mm;

3444
	tlb_gather_mmu(&tlb, mm, start, end);
3445 3446
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
	tlb_finish_mmu(&tlb, start, end);
3447 3448
}

3449 3450 3451 3452 3453 3454
/*
 * 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.
 */
3455 3456
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
3457
{
3458
	struct hstate *h = hstate_vma(vma);
3459 3460 3461 3462 3463 3464 3465 3466
	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.
	 */
3467
	address = address & huge_page_mask(h);
3468 3469
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
3470
	mapping = vma->vm_file->f_mapping;
3471

3472 3473 3474 3475 3476
	/*
	 * 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
	 */
3477
	i_mmap_lock_write(mapping);
3478
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3479 3480 3481 3482
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

3483 3484 3485 3486 3487 3488 3489 3490
		/*
		 * 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;

3491 3492 3493 3494 3495 3496 3497 3498
		/*
		 * 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))
3499 3500
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
3501
	}
3502
	i_mmap_unlock_write(mapping);
3503 3504
}

3505 3506
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3507 3508 3509
 * 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.
3510
 */
3511
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3512
		       unsigned long address, pte_t *ptep,
3513
		       struct page *pagecache_page, spinlock_t *ptl)
3514
{
3515
	pte_t pte;
3516
	struct hstate *h = hstate_vma(vma);
3517
	struct page *old_page, *new_page;
3518
	int ret = 0, outside_reserve = 0;
3519 3520
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
3521
	unsigned long haddr = address & huge_page_mask(h);
3522

3523
	pte = huge_ptep_get(ptep);
3524 3525
	old_page = pte_page(pte);

3526
retry_avoidcopy:
3527 3528
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
3529
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3530
		page_move_anon_rmap(old_page, vma);
3531
		set_huge_ptep_writable(vma, haddr, ptep);
N
Nick Piggin 已提交
3532
		return 0;
3533 3534
	}

3535 3536 3537 3538 3539 3540 3541 3542 3543
	/*
	 * 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.
	 */
3544
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3545 3546 3547
			old_page != pagecache_page)
		outside_reserve = 1;

3548
	get_page(old_page);
3549

3550 3551 3552 3553
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
3554
	spin_unlock(ptl);
3555
	new_page = alloc_huge_page(vma, haddr, outside_reserve);
3556

3557
	if (IS_ERR(new_page)) {
3558 3559 3560 3561 3562 3563 3564 3565
		/*
		 * 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) {
3566
			put_page(old_page);
3567
			BUG_ON(huge_pte_none(pte));
3568
			unmap_ref_private(mm, vma, old_page, haddr);
3569 3570
			BUG_ON(huge_pte_none(pte));
			spin_lock(ptl);
3571
			ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
3572 3573 3574 3575 3576 3577 3578 3579
			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;
3580 3581
		}

3582 3583 3584
		ret = (PTR_ERR(new_page) == -ENOMEM) ?
			VM_FAULT_OOM : VM_FAULT_SIGBUS;
		goto out_release_old;
3585 3586
	}

3587 3588 3589 3590
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
3591
	if (unlikely(anon_vma_prepare(vma))) {
3592 3593
		ret = VM_FAULT_OOM;
		goto out_release_all;
3594
	}
3595

3596
	copy_user_huge_page(new_page, old_page, address, vma,
A
Andrea Arcangeli 已提交
3597
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
3598
	__SetPageUptodate(new_page);
3599
	set_page_huge_active(new_page);
3600

3601
	mmun_start = haddr;
3602 3603
	mmun_end = mmun_start + huge_page_size(h);
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3604

3605
	/*
3606
	 * Retake the page table lock to check for racing updates
3607 3608
	 * before the page tables are altered
	 */
3609
	spin_lock(ptl);
3610
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
3611
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3612 3613
		ClearPagePrivate(new_page);

3614
		/* Break COW */
3615
		huge_ptep_clear_flush(vma, haddr, ptep);
3616
		mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
3617
		set_huge_pte_at(mm, haddr, ptep,
3618
				make_huge_pte(vma, new_page, 1));
3619
		page_remove_rmap(old_page, true);
3620
		hugepage_add_new_anon_rmap(new_page, vma, haddr);
3621 3622 3623
		/* Make the old page be freed below */
		new_page = old_page;
	}
3624
	spin_unlock(ptl);
3625
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3626
out_release_all:
3627
	restore_reserve_on_error(h, vma, haddr, new_page);
3628
	put_page(new_page);
3629
out_release_old:
3630
	put_page(old_page);
3631

3632 3633
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
3634 3635
}

3636
/* Return the pagecache page at a given address within a VMA */
3637 3638
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
3639 3640
{
	struct address_space *mapping;
3641
	pgoff_t idx;
3642 3643

	mapping = vma->vm_file->f_mapping;
3644
	idx = vma_hugecache_offset(h, vma, address);
3645 3646 3647 3648

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
3649 3650 3651 3652 3653
/*
 * 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
3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668
			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;
}

3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685
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;
}

3686
static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
3687 3688
			   struct address_space *mapping, pgoff_t idx,
			   unsigned long address, pte_t *ptep, unsigned int flags)
3689
{
3690
	struct hstate *h = hstate_vma(vma);
3691
	int ret = VM_FAULT_SIGBUS;
3692
	int anon_rmap = 0;
A
Adam Litke 已提交
3693 3694
	unsigned long size;
	struct page *page;
3695
	pte_t new_pte;
3696
	spinlock_t *ptl;
3697
	unsigned long haddr = address & huge_page_mask(h);
A
Adam Litke 已提交
3698

3699 3700 3701
	/*
	 * 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
3702
	 * COW. Warn that such a situation has occurred as it may not be obvious
3703 3704
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3705
		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3706
			   current->pid);
3707 3708 3709
		return ret;
	}

A
Adam Litke 已提交
3710 3711 3712 3713
	/*
	 * Use page lock to guard against racing truncation
	 * before we get page_table_lock.
	 */
3714 3715 3716
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
3717
		size = i_size_read(mapping->host) >> huge_page_shift(h);
3718 3719
		if (idx >= size)
			goto out;
3720 3721 3722 3723 3724 3725 3726 3727

		/*
		 * Check for page in userfault range
		 */
		if (userfaultfd_missing(vma)) {
			u32 hash;
			struct vm_fault vmf = {
				.vma = vma,
3728
				.address = haddr,
3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743 3744
				.flags = flags,
				/*
				 * Hard to debug if it ends up being
				 * used by a callee that assumes
				 * something about the other
				 * uninitialized fields... same as in
				 * memory.c
				 */
			};

			/*
			 * hugetlb_fault_mutex must be dropped before
			 * handling userfault.  Reacquire after handling
			 * fault to make calling code simpler.
			 */
			hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping,
3745
							idx, haddr);
3746 3747 3748 3749 3750 3751
			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
			ret = handle_userfault(&vmf, VM_UFFD_MISSING);
			mutex_lock(&hugetlb_fault_mutex_table[hash]);
			goto out;
		}

3752
		page = alloc_huge_page(vma, haddr, 0);
3753
		if (IS_ERR(page)) {
3754 3755 3756 3757 3758
			ret = PTR_ERR(page);
			if (ret == -ENOMEM)
				ret = VM_FAULT_OOM;
			else
				ret = VM_FAULT_SIGBUS;
3759 3760
			goto out;
		}
A
Andrea Arcangeli 已提交
3761
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
3762
		__SetPageUptodate(page);
3763
		set_page_huge_active(page);
3764

3765
		if (vma->vm_flags & VM_MAYSHARE) {
3766
			int err = huge_add_to_page_cache(page, mapping, idx);
3767 3768 3769 3770 3771 3772
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
3773
		} else {
3774
			lock_page(page);
3775 3776 3777 3778
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
3779
			anon_rmap = 1;
3780
		}
3781
	} else {
3782 3783 3784 3785 3786 3787
		/*
		 * 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))) {
3788
			ret = VM_FAULT_HWPOISON |
3789
				VM_FAULT_SET_HINDEX(hstate_index(h));
3790 3791
			goto backout_unlocked;
		}
3792
	}
3793

3794 3795 3796 3797 3798 3799
	/*
	 * 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.
	 */
3800
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3801
		if (vma_needs_reservation(h, vma, haddr) < 0) {
3802 3803 3804
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
3805
		/* Just decrements count, does not deallocate */
3806
		vma_end_reservation(h, vma, haddr);
3807
	}
3808

3809
	ptl = huge_pte_lock(h, mm, ptep);
3810
	size = i_size_read(mapping->host) >> huge_page_shift(h);
A
Adam Litke 已提交
3811 3812 3813
	if (idx >= size)
		goto backout;

N
Nick Piggin 已提交
3814
	ret = 0;
3815
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
3816 3817
		goto backout;

3818 3819
	if (anon_rmap) {
		ClearPagePrivate(page);
3820
		hugepage_add_new_anon_rmap(page, vma, haddr);
3821
	} else
3822
		page_dup_rmap(page, true);
3823 3824
	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
				&& (vma->vm_flags & VM_SHARED)));
3825
	set_huge_pte_at(mm, haddr, ptep, new_pte);
3826

3827
	hugetlb_count_add(pages_per_huge_page(h), mm);
3828
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3829
		/* Optimization, do the COW without a second fault */
3830
		ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
3831 3832
	}

3833
	spin_unlock(ptl);
A
Adam Litke 已提交
3834 3835
	unlock_page(page);
out:
3836
	return ret;
A
Adam Litke 已提交
3837 3838

backout:
3839
	spin_unlock(ptl);
3840
backout_unlocked:
A
Adam Litke 已提交
3841
	unlock_page(page);
3842
	restore_reserve_on_error(h, vma, haddr, page);
A
Adam Litke 已提交
3843 3844
	put_page(page);
	goto out;
3845 3846
}

3847
#ifdef CONFIG_SMP
3848
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3849 3850 3851 3852 3853 3854 3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866 3867 3868 3869 3870 3871 3872
			    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.
 */
3873
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3874 3875 3876 3877 3878 3879 3880 3881
			    struct vm_area_struct *vma,
			    struct address_space *mapping,
			    pgoff_t idx, unsigned long address)
{
	return 0;
}
#endif

3882
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3883
			unsigned long address, unsigned int flags)
3884
{
3885
	pte_t *ptep, entry;
3886
	spinlock_t *ptl;
3887
	int ret;
3888 3889
	u32 hash;
	pgoff_t idx;
3890
	struct page *page = NULL;
3891
	struct page *pagecache_page = NULL;
3892
	struct hstate *h = hstate_vma(vma);
3893
	struct address_space *mapping;
3894
	int need_wait_lock = 0;
3895
	unsigned long haddr = address & huge_page_mask(h);
3896

3897
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
3898 3899
	if (ptep) {
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
3900
		if (unlikely(is_hugetlb_entry_migration(entry))) {
3901
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
3902 3903
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3904
			return VM_FAULT_HWPOISON_LARGE |
3905
				VM_FAULT_SET_HINDEX(hstate_index(h));
3906
	} else {
3907
		ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
3908 3909
		if (!ptep)
			return VM_FAULT_OOM;
3910 3911
	}

3912
	mapping = vma->vm_file->f_mapping;
3913
	idx = vma_hugecache_offset(h, vma, haddr);
3914

3915 3916 3917 3918 3919
	/*
	 * 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.
	 */
3920
	hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, haddr);
3921
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
3922

3923 3924
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
3925
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3926
		goto out_mutex;
3927
	}
3928

N
Nick Piggin 已提交
3929
	ret = 0;
3930

3931 3932 3933 3934 3935 3936 3937 3938 3939 3940
	/*
	 * 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;

3941 3942 3943 3944 3945 3946 3947 3948
	/*
	 * 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.
	 */
3949
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3950
		if (vma_needs_reservation(h, vma, haddr) < 0) {
3951
			ret = VM_FAULT_OOM;
3952
			goto out_mutex;
3953
		}
3954
		/* Just decrements count, does not deallocate */
3955
		vma_end_reservation(h, vma, haddr);
3956

3957
		if (!(vma->vm_flags & VM_MAYSHARE))
3958
			pagecache_page = hugetlbfs_pagecache_page(h,
3959
								vma, haddr);
3960 3961
	}

3962 3963 3964 3965 3966 3967
	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;

3968 3969 3970 3971 3972 3973 3974
	/*
	 * 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)
3975 3976 3977 3978
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
3979

3980
	get_page(page);
3981

3982
	if (flags & FAULT_FLAG_WRITE) {
3983
		if (!huge_pte_write(entry)) {
3984
			ret = hugetlb_cow(mm, vma, address, ptep,
3985
					  pagecache_page, ptl);
3986
			goto out_put_page;
3987
		}
3988
		entry = huge_pte_mkdirty(entry);
3989 3990
	}
	entry = pte_mkyoung(entry);
3991
	if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
3992
						flags & FAULT_FLAG_WRITE))
3993
		update_mmu_cache(vma, haddr, ptep);
3994 3995 3996 3997
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
3998 3999
out_ptl:
	spin_unlock(ptl);
4000 4001 4002 4003 4004

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
4005
out_mutex:
4006
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4007 4008 4009 4010 4011 4012 4013 4014 4015
	/*
	 * 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);
4016
	return ret;
4017 4018
}

4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029
/*
 * Used by userfaultfd UFFDIO_COPY.  Based on mcopy_atomic_pte with
 * modifications for huge pages.
 */
int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
			    pte_t *dst_pte,
			    struct vm_area_struct *dst_vma,
			    unsigned long dst_addr,
			    unsigned long src_addr,
			    struct page **pagep)
{
4030 4031 4032
	struct address_space *mapping;
	pgoff_t idx;
	unsigned long size;
4033
	int vm_shared = dst_vma->vm_flags & VM_SHARED;
4034 4035 4036 4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047
	struct hstate *h = hstate_vma(dst_vma);
	pte_t _dst_pte;
	spinlock_t *ptl;
	int ret;
	struct page *page;

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

		ret = copy_huge_page_from_user(page,
						(const void __user *) src_addr,
4048
						pages_per_huge_page(h), false);
4049 4050 4051 4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069

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

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

4070 4071 4072
	mapping = dst_vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, dst_vma, dst_addr);

4073 4074 4075 4076
	/*
	 * If shared, add to page cache
	 */
	if (vm_shared) {
4077 4078 4079 4080
		size = i_size_read(mapping->host) >> huge_page_shift(h);
		ret = -EFAULT;
		if (idx >= size)
			goto out_release_nounlock;
4081

4082 4083 4084 4085 4086 4087
		/*
		 * Serialization between remove_inode_hugepages() and
		 * huge_add_to_page_cache() below happens through the
		 * hugetlb_fault_mutex_table that here must be hold by
		 * the caller.
		 */
4088 4089 4090 4091 4092
		ret = huge_add_to_page_cache(page, mapping, idx);
		if (ret)
			goto out_release_nounlock;
	}

4093 4094 4095
	ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
	spin_lock(ptl);

4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109
	/*
	 * Recheck the i_size after holding PT lock to make sure not
	 * to leave any page mapped (as page_mapped()) beyond the end
	 * of the i_size (remove_inode_hugepages() is strict about
	 * enforcing that). If we bail out here, we'll also leave a
	 * page in the radix tree in the vm_shared case beyond the end
	 * of the i_size, but remove_inode_hugepages() will take care
	 * of it as soon as we drop the hugetlb_fault_mutex_table.
	 */
	size = i_size_read(mapping->host) >> huge_page_shift(h);
	ret = -EFAULT;
	if (idx >= size)
		goto out_release_unlock;

4110 4111 4112 4113
	ret = -EEXIST;
	if (!huge_pte_none(huge_ptep_get(dst_pte)))
		goto out_release_unlock;

4114 4115 4116 4117 4118 4119
	if (vm_shared) {
		page_dup_rmap(page, true);
	} else {
		ClearPagePrivate(page);
		hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
	}
4120 4121 4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135

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

	set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);

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

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

	spin_unlock(ptl);
4136 4137
	if (vm_shared)
		unlock_page(page);
4138 4139 4140 4141 4142
	ret = 0;
out:
	return ret;
out_release_unlock:
	spin_unlock(ptl);
4143 4144
	if (vm_shared)
		unlock_page(page);
4145
out_release_nounlock:
4146 4147 4148 4149
	put_page(page);
	goto out;
}

4150 4151 4152
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,
4153
			 long i, unsigned int flags, int *nonblocking)
D
David Gibson 已提交
4154
{
4155 4156
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
4157
	unsigned long remainder = *nr_pages;
4158
	struct hstate *h = hstate_vma(vma);
4159
	int err = -EFAULT;
D
David Gibson 已提交
4160 4161

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
4162
		pte_t *pte;
4163
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
4164
		int absent;
A
Adam Litke 已提交
4165
		struct page *page;
D
David Gibson 已提交
4166

4167 4168 4169 4170 4171 4172 4173 4174 4175
		/*
		 * 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
4176 4177
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
4178
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
4179
		 * first, for the page indexing below to work.
4180 4181
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
4182
		 */
4183 4184
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
				      huge_page_size(h));
4185 4186
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
4187 4188 4189 4190
		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
4191 4192 4193 4194
		 * 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
4195
		 */
H
Hugh Dickins 已提交
4196 4197
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4198 4199
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
4200 4201 4202
			remainder = 0;
			break;
		}
D
David Gibson 已提交
4203

4204 4205 4206 4207 4208 4209 4210 4211 4212 4213 4214
		/*
		 * 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)) ||
4215 4216
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
A
Adam Litke 已提交
4217
			int ret;
4218
			unsigned int fault_flags = 0;
D
David Gibson 已提交
4219

4220 4221
			if (pte)
				spin_unlock(ptl);
4222 4223 4224 4225 4226 4227 4228 4229 4230 4231 4232 4233 4234 4235
			if (flags & FOLL_WRITE)
				fault_flags |= FAULT_FLAG_WRITE;
			if (nonblocking)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY;
			if (flags & FOLL_NOWAIT)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_RETRY_NOWAIT;
			if (flags & FOLL_TRIED) {
				VM_WARN_ON_ONCE(fault_flags &
						FAULT_FLAG_ALLOW_RETRY);
				fault_flags |= FAULT_FLAG_TRIED;
			}
			ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
			if (ret & VM_FAULT_ERROR) {
4236
				err = vm_fault_to_errno(ret, flags);
4237 4238 4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251 4252 4253 4254 4255
				remainder = 0;
				break;
			}
			if (ret & VM_FAULT_RETRY) {
				if (nonblocking)
					*nonblocking = 0;
				*nr_pages = 0;
				/*
				 * VM_FAULT_RETRY must not return an
				 * error, it will return zero
				 * instead.
				 *
				 * No need to update "position" as the
				 * caller will not check it after
				 * *nr_pages is set to 0.
				 */
				return i;
			}
			continue;
A
Adam Litke 已提交
4256 4257
		}

4258
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4259
		page = pte_page(huge_ptep_get(pte));
4260
same_page:
4261
		if (pages) {
H
Hugh Dickins 已提交
4262
			pages[i] = mem_map_offset(page, pfn_offset);
4263
			get_page(pages[i]);
4264
		}
D
David Gibson 已提交
4265 4266 4267 4268 4269

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
4270
		++pfn_offset;
D
David Gibson 已提交
4271 4272
		--remainder;
		++i;
4273
		if (vaddr < vma->vm_end && remainder &&
4274
				pfn_offset < pages_per_huge_page(h)) {
4275 4276 4277 4278 4279 4280
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
4281
		spin_unlock(ptl);
D
David Gibson 已提交
4282
	}
4283
	*nr_pages = remainder;
4284 4285 4286 4287 4288
	/*
	 * setting position is actually required only if remainder is
	 * not zero but it's faster not to add a "if (remainder)"
	 * branch.
	 */
D
David Gibson 已提交
4289 4290
	*position = vaddr;

4291
	return i ? i : err;
D
David Gibson 已提交
4292
}
4293

4294 4295 4296 4297 4298 4299 4300 4301
#ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE
/*
 * ARCHes with special requirements for evicting HUGETLB backing TLB entries can
 * implement this.
 */
#define flush_hugetlb_tlb_range(vma, addr, end)	flush_tlb_range(vma, addr, end)
#endif

4302
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4303 4304 4305 4306 4307 4308
		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;
4309
	struct hstate *h = hstate_vma(vma);
4310
	unsigned long pages = 0;
4311 4312 4313 4314

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

4315
	mmu_notifier_invalidate_range_start(mm, start, end);
4316
	i_mmap_lock_write(vma->vm_file->f_mapping);
4317
	for (; address < end; address += huge_page_size(h)) {
4318
		spinlock_t *ptl;
4319
		ptep = huge_pte_offset(mm, address, huge_page_size(h));
4320 4321
		if (!ptep)
			continue;
4322
		ptl = huge_pte_lock(h, mm, ptep);
4323 4324
		if (huge_pmd_unshare(mm, &address, ptep)) {
			pages++;
4325
			spin_unlock(ptl);
4326
			continue;
4327
		}
4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340
		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);
4341 4342
				set_huge_swap_pte_at(mm, address, ptep,
						     newpte, huge_page_size(h));
4343 4344 4345 4346 4347 4348
				pages++;
			}
			spin_unlock(ptl);
			continue;
		}
		if (!huge_pte_none(pte)) {
4349
			pte = huge_ptep_get_and_clear(mm, address, ptep);
4350
			pte = pte_mkhuge(huge_pte_modify(pte, newprot));
4351
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
4352
			set_huge_pte_at(mm, address, ptep, pte);
4353
			pages++;
4354
		}
4355
		spin_unlock(ptl);
4356
	}
4357
	/*
4358
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4359
	 * may have cleared our pud entry and done put_page on the page table:
4360
	 * once we release i_mmap_rwsem, another task can do the final put_page
4361 4362
	 * and that page table be reused and filled with junk.
	 */
4363
	flush_hugetlb_tlb_range(vma, start, end);
4364 4365 4366 4367
	/*
	 * No need to call mmu_notifier_invalidate_range() we are downgrading
	 * page table protection not changing it to point to a new page.
	 *
4368
	 * See Documentation/vm/mmu_notifier.rst
4369
	 */
4370
	i_mmap_unlock_write(vma->vm_file->f_mapping);
4371
	mmu_notifier_invalidate_range_end(mm, start, end);
4372 4373

	return pages << h->order;
4374 4375
}

4376 4377
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
4378
					struct vm_area_struct *vma,
4379
					vm_flags_t vm_flags)
4380
{
4381
	long ret, chg;
4382
	struct hstate *h = hstate_inode(inode);
4383
	struct hugepage_subpool *spool = subpool_inode(inode);
4384
	struct resv_map *resv_map;
4385
	long gbl_reserve;
4386

4387 4388 4389 4390 4391 4392
	/* This should never happen */
	if (from > to) {
		VM_WARN(1, "%s called with a negative range\n", __func__);
		return -EINVAL;
	}

4393 4394 4395
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
4396
	 * without using reserves
4397
	 */
4398
	if (vm_flags & VM_NORESERVE)
4399 4400
		return 0;

4401 4402 4403 4404 4405 4406
	/*
	 * 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
	 */
4407
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
4408
		resv_map = inode_resv_map(inode);
4409

4410
		chg = region_chg(resv_map, from, to);
4411 4412 4413

	} else {
		resv_map = resv_map_alloc();
4414 4415 4416
		if (!resv_map)
			return -ENOMEM;

4417
		chg = to - from;
4418

4419 4420 4421 4422
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

4423 4424 4425 4426
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
4427

4428 4429 4430 4431 4432 4433 4434
	/*
	 * 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) {
4435 4436 4437
		ret = -ENOSPC;
		goto out_err;
	}
4438 4439

	/*
4440
	 * Check enough hugepages are available for the reservation.
4441
	 * Hand the pages back to the subpool if there are not
4442
	 */
4443
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
4444
	if (ret < 0) {
4445 4446
		/* put back original number of pages, chg */
		(void)hugepage_subpool_put_pages(spool, chg);
4447
		goto out_err;
K
Ken Chen 已提交
4448
	}
4449 4450 4451 4452 4453 4454 4455 4456 4457 4458 4459 4460

	/*
	 * 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
	 */
4461 4462 4463 4464 4465 4466 4467 4468 4469 4470 4471 4472 4473 4474 4475 4476 4477 4478
	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);
		}
	}
4479
	return 0;
4480
out_err:
4481
	if (!vma || vma->vm_flags & VM_MAYSHARE)
4482 4483 4484
		/* Don't call region_abort if region_chg failed */
		if (chg >= 0)
			region_abort(resv_map, from, to);
J
Joonsoo Kim 已提交
4485 4486
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
4487
	return ret;
4488 4489
}

4490 4491
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
4492
{
4493
	struct hstate *h = hstate_inode(inode);
4494
	struct resv_map *resv_map = inode_resv_map(inode);
4495
	long chg = 0;
4496
	struct hugepage_subpool *spool = subpool_inode(inode);
4497
	long gbl_reserve;
K
Ken Chen 已提交
4498

4499 4500 4501 4502 4503 4504 4505 4506 4507 4508 4509
	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
4510
	spin_lock(&inode->i_lock);
4511
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
4512 4513
	spin_unlock(&inode->i_lock);

4514 4515 4516 4517 4518 4519
	/*
	 * 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);
4520 4521

	return 0;
4522
}
4523

4524 4525 4526 4527 4528 4529 4530 4531 4532 4533 4534
#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
4535 4536
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4537 4538 4539 4540 4541 4542 4543 4544 4545 4546 4547 4548 4549

	/*
	 * 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;
}

4550
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4551 4552 4553 4554 4555 4556 4557 4558 4559
{
	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)
4560 4561
		return true;
	return false;
4562 4563 4564 4565 4566 4567 4568
}

/*
 * 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
4569
 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4570 4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582
 * 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;
4583
	spinlock_t *ptl;
4584 4585 4586 4587

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

4588
	i_mmap_lock_write(mapping);
4589 4590 4591 4592 4593 4594
	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

		saddr = page_table_shareable(svma, vma, addr, idx);
		if (saddr) {
4595 4596
			spte = huge_pte_offset(svma->vm_mm, saddr,
					       vma_mmu_pagesize(svma));
4597 4598 4599 4600 4601 4602 4603 4604 4605 4606
			if (spte) {
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

4607
	ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
4608
	if (pud_none(*pud)) {
4609 4610
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
4611
		mm_inc_nr_pmds(mm);
4612
	} else {
4613
		put_page(virt_to_page(spte));
4614
	}
4615
	spin_unlock(ptl);
4616 4617
out:
	pte = (pte_t *)pmd_alloc(mm, pud, addr);
4618
	i_mmap_unlock_write(mapping);
4619 4620 4621 4622 4623 4624 4625 4626 4627 4628
	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.
 *
4629
 * called with page table lock held.
4630 4631 4632 4633 4634 4635 4636
 *
 * 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);
4637 4638
	p4d_t *p4d = p4d_offset(pgd, *addr);
	pud_t *pud = pud_offset(p4d, *addr);
4639 4640 4641 4642 4643 4644 4645

	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));
4646
	mm_dec_nr_pmds(mm);
4647 4648 4649
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
4650 4651 4652 4653 4654 4655
#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;
}
4656 4657 4658 4659 4660

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	return 0;
}
4661
#define want_pmd_share()	(0)
4662 4663
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

4664 4665 4666 4667 4668
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
4669
	p4d_t *p4d;
4670 4671 4672 4673
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
4674 4675 4676
	p4d = p4d_alloc(mm, pgd, addr);
	if (!p4d)
		return NULL;
4677
	pud = pud_alloc(mm, p4d, addr);
4678 4679 4680 4681 4682 4683 4684 4685 4686 4687 4688
	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);
		}
	}
4689
	BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
4690 4691 4692 4693

	return pte;
}

4694 4695 4696 4697 4698 4699 4700 4701 4702
/*
 * huge_pte_offset() - Walk the page table to resolve the hugepage
 * entry at address @addr
 *
 * Return: Pointer to page table or swap entry (PUD or PMD) for
 * address @addr, or NULL if a p*d_none() entry is encountered and the
 * size @sz doesn't match the hugepage size at this level of the page
 * table.
 */
4703 4704
pte_t *huge_pte_offset(struct mm_struct *mm,
		       unsigned long addr, unsigned long sz)
4705 4706
{
	pgd_t *pgd;
4707
	p4d_t *p4d;
4708
	pud_t *pud;
4709
	pmd_t *pmd;
4710 4711

	pgd = pgd_offset(mm, addr);
4712 4713 4714 4715 4716
	if (!pgd_present(*pgd))
		return NULL;
	p4d = p4d_offset(pgd, addr);
	if (!p4d_present(*p4d))
		return NULL;
4717

4718
	pud = pud_offset(p4d, addr);
4719
	if (sz != PUD_SIZE && pud_none(*pud))
4720
		return NULL;
4721 4722
	/* hugepage or swap? */
	if (pud_huge(*pud) || !pud_present(*pud))
4723
		return (pte_t *)pud;
4724

4725
	pmd = pmd_offset(pud, addr);
4726 4727 4728 4729 4730 4731 4732
	if (sz != PMD_SIZE && pmd_none(*pmd))
		return NULL;
	/* hugepage or swap? */
	if (pmd_huge(*pmd) || !pmd_present(*pmd))
		return (pte_t *)pmd;

	return NULL;
4733 4734
}

4735 4736 4737 4738 4739 4740 4741 4742 4743 4744 4745 4746 4747
#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);
}

4748 4749 4750 4751 4752 4753 4754 4755
struct page * __weak
follow_huge_pd(struct vm_area_struct *vma,
	       unsigned long address, hugepd_t hpd, int flags, int pdshift)
{
	WARN(1, "hugepd follow called with no support for hugepage directory format\n");
	return NULL;
}

4756
struct page * __weak
4757
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4758
		pmd_t *pmd, int flags)
4759
{
4760 4761
	struct page *page = NULL;
	spinlock_t *ptl;
4762
	pte_t pte;
4763 4764 4765 4766 4767 4768 4769 4770 4771
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;
4772 4773
	pte = huge_ptep_get((pte_t *)pmd);
	if (pte_present(pte)) {
4774
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4775 4776 4777
		if (flags & FOLL_GET)
			get_page(page);
	} else {
4778
		if (is_hugetlb_entry_migration(pte)) {
4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789
			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);
4790 4791 4792
	return page;
}

4793
struct page * __weak
4794
follow_huge_pud(struct mm_struct *mm, unsigned long address,
4795
		pud_t *pud, int flags)
4796
{
4797 4798
	if (flags & FOLL_GET)
		return NULL;
4799

4800
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4801 4802
}

4803 4804 4805 4806 4807 4808 4809 4810 4811
struct page * __weak
follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
{
	if (flags & FOLL_GET)
		return NULL;

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

4812 4813
bool isolate_huge_page(struct page *page, struct list_head *list)
{
4814 4815
	bool ret = true;

4816
	VM_BUG_ON_PAGE(!PageHead(page), page);
4817
	spin_lock(&hugetlb_lock);
4818 4819 4820 4821 4822
	if (!page_huge_active(page) || !get_page_unless_zero(page)) {
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
4823
	list_move_tail(&page->lru, list);
4824
unlock:
4825
	spin_unlock(&hugetlb_lock);
4826
	return ret;
4827 4828 4829 4830
}

void putback_active_hugepage(struct page *page)
{
4831
	VM_BUG_ON_PAGE(!PageHead(page), page);
4832
	spin_lock(&hugetlb_lock);
4833
	set_page_huge_active(page);
4834 4835 4836 4837
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}
4838 4839 4840 4841 4842 4843 4844 4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858 4859 4860 4861 4862 4863 4864 4865 4866 4867 4868 4869 4870

void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
{
	struct hstate *h = page_hstate(oldpage);

	hugetlb_cgroup_migrate(oldpage, newpage);
	set_page_owner_migrate_reason(newpage, reason);

	/*
	 * transfer temporary state of the new huge page. This is
	 * reverse to other transitions because the newpage is going to
	 * be final while the old one will be freed so it takes over
	 * the temporary status.
	 *
	 * Also note that we have to transfer the per-node surplus state
	 * here as well otherwise the global surplus count will not match
	 * the per-node's.
	 */
	if (PageHugeTemporary(newpage)) {
		int old_nid = page_to_nid(oldpage);
		int new_nid = page_to_nid(newpage);

		SetPageHugeTemporary(oldpage);
		ClearPageHugeTemporary(newpage);

		spin_lock(&hugetlb_lock);
		if (h->surplus_huge_pages_node[old_nid]) {
			h->surplus_huge_pages_node[old_nid]--;
			h->surplus_huge_pages_node[new_nid]++;
		}
		spin_unlock(&hugetlb_lock);
	}
}