hugetlb.c 119.7 KB
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/*
 * Generic hugetlb support.
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 * (C) Nadia Yvette Chambers, April 2004
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 */
#include <linux/list.h>
#include <linux/init.h>
#include <linux/mm.h>
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#include <linux/seq_file.h>
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#include <linux/sysctl.h>
#include <linux/highmem.h>
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#include <linux/mmu_notifier.h>
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#include <linux/nodemask.h>
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#include <linux/pagemap.h>
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#include <linux/mempolicy.h>
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#include <linux/compiler.h>
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#include <linux/cpuset.h>
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#include <linux/mutex.h>
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#include <linux/bootmem.h>
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#include <linux/sysfs.h>
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#include <linux/slab.h>
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#include <linux/rmap.h>
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#include <linux/swap.h>
#include <linux/swapops.h>
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#include <linux/page-isolation.h>
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#include <linux/jhash.h>
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#include <asm/page.h>
#include <asm/pgtable.h>
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#include <asm/tlb.h>
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#include <linux/io.h>
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#include <linux/hugetlb.h>
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#include <linux/hugetlb_cgroup.h>
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#include <linux/node.h>
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#include "internal.h"
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int hugepages_treat_as_movable;
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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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/*
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 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
 * free_huge_pages, and surplus_huge_pages.
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 */
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DEFINE_SPINLOCK(hugetlb_lock);
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/*
 * Serializes faults on the same logical page.  This is used to
 * prevent spurious OOMs when the hugepage pool is fully utilized.
 */
static int num_fault_mutexes;
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struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
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/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);

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

	spin_unlock(&spool->lock);

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

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

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

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

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

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

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

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

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

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

179
	if (!spool)
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		return delta;
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	spin_lock(&spool->lock);
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	if (spool->max_hpages != -1)		/* maximum size accounting */
		spool->used_hpages -= delta;

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

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

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

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

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

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

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

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

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

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

		add += t - f;
		goto out_locked;
	}

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

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

		/* If this area reaches higher then extend our area to
		 * include it completely.  If this is not the first area
		 * which we intend to reuse, free it. */
		if (rg->to > t)
			t = rg->to;
		if (rg != nrg) {
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			/* Decrement return value by the deleted range.
			 * Another range will span this area so that by
			 * end of routine add will be >= zero
			 */
			add -= (rg->to - rg->from);
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			list_del(&rg->link);
			kfree(rg);
		}
	}
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	add += (nrg->from - f);		/* Added to beginning of region */
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	nrg->from = f;
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	add += t - nrg->to;		/* Added to end of region */
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	nrg->to = t;
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out_locked:
	resv->adds_in_progress--;
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	spin_unlock(&resv->lock);
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	VM_BUG_ON(add < 0);
	return add;
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}

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

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

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

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

		trg = kmalloc(sizeof(*trg), GFP_KERNEL);
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		if (!trg) {
			kfree(nrg);
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			return -ENOMEM;
380
		}
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		spin_lock(&resv->lock);
		list_add(&trg->link, &resv->region_cache);
		resv->region_cache_count++;
		goto retry_locked;
	}

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

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

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

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

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

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

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/*
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 * Delete the specified range [f, t) from the reserve map.  If the
 * t parameter is LONG_MAX, this indicates that ALL regions after f
 * should be deleted.  Locate the regions which intersect [f, t)
 * and either trim, delete or split the existing regions.
 *
 * Returns the number of huge pages deleted from the reserve map.
 * In the normal case, the return value is zero or more.  In the
 * case where a region must be split, a new region descriptor must
 * be allocated.  If the allocation fails, -ENOMEM will be returned.
 * NOTE: If the parameter t == LONG_MAX, then we will never split
 * a region and possibly return -ENOMEM.  Callers specifying
 * t == LONG_MAX do not need to check for -ENOMEM error.
479
 */
480
static long region_del(struct resv_map *resv, long f, long t)
481
{
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	struct list_head *head = &resv->regions;
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	struct file_region *rg, *trg;
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	struct file_region *nrg = NULL;
	long del = 0;
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retry:
488
	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))
498
			continue;
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500
		if (rg->from >= t)
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			break;

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

			del += t - f;

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

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

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

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

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

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

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

		hugetlb_acct_memory(h, 1);
	}
}

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/*
 * Count and return the number of huge pages in the reserve map
 * that intersect with the range [f, t).
 */
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static long region_count(struct resv_map *resv, long f, long t)
588
{
589
	struct list_head *head = &resv->regions;
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	struct file_region *rg;
	long chg = 0;

593
	spin_lock(&resv->lock);
594 595
	/* Locate each segment we overlap with, and count that overlap. */
	list_for_each_entry(rg, head, link) {
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		long seg_from;
		long seg_to;
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		if (rg->to <= f)
			continue;
		if (rg->from >= t)
			break;

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

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

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/*
 * Convert the address within this vma to the page offset within
 * the mapping, in pagecache page units; huge pages here.
 */
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static pgoff_t vma_hugecache_offset(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
620
{
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	return ((address - vma->vm_start) >> huge_page_shift(h)) +
			(vma->vm_pgoff >> huge_page_order(h));
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}

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pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
				     unsigned long address)
{
	return vma_hugecache_offset(hstate_vma(vma), vma, address);
}
630
EXPORT_SYMBOL_GPL(linear_hugepage_index);
631

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

	if (!is_vm_hugetlb_page(vma))
		return PAGE_SIZE;

	hstate = hstate_vma(vma);

645
	return 1UL << huge_page_shift(hstate);
646
}
647
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
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/*
 * Return the page size being used by the MMU to back a VMA. In the majority
 * of cases, the page size used by the kernel matches the MMU size. On
 * architectures where it differs, an architecture-specific version of this
 * function is required.
 */
#ifndef vma_mmu_pagesize
unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
{
	return vma_kernel_pagesize(vma);
}
#endif

662 663 664 665 666 667 668
/*
 * 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)
669
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
670

671 672 673 674 675 676 677 678 679
/*
 * 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.
680 681 682 683 684 685 686 687 688
 *
 * 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.
689
 */
690 691 692 693 694 695 696 697 698 699 700
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;
}

701
struct resv_map *resv_map_alloc(void)
702 703
{
	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
704 705 706 707 708
	struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);

	if (!resv_map || !rg) {
		kfree(resv_map);
		kfree(rg);
709
		return NULL;
710
	}
711 712

	kref_init(&resv_map->refs);
713
	spin_lock_init(&resv_map->lock);
714 715
	INIT_LIST_HEAD(&resv_map->regions);

716 717 718 719 720 721
	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;

722 723 724
	return resv_map;
}

725
void resv_map_release(struct kref *ref)
726 727
{
	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
728 729
	struct list_head *head = &resv_map->region_cache;
	struct file_region *rg, *trg;
730 731

	/* Clear out any active regions before we release the map. */
732
	region_del(resv_map, 0, LONG_MAX);
733 734 735 736 737 738 739 740 741

	/* ... 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);

742 743 744
	kfree(resv_map);
}

745 746 747 748 749
static inline struct resv_map *inode_resv_map(struct inode *inode)
{
	return inode->i_mapping->private_data;
}

750
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
751
{
752
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
753 754 755 756 757 758 759
	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 {
760 761
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
762
	}
763 764
}

765
static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
766
{
767 768
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
769

770 771
	set_vma_private_data(vma, (get_vma_private_data(vma) &
				HPAGE_RESV_MASK) | (unsigned long)map);
772 773 774 775
}

static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
{
776 777
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
778 779

	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
780 781 782 783
}

static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
{
784
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
785 786

	return (get_vma_private_data(vma) & flag) != 0;
787 788
}

789
/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
790 791
void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
792
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
793
	if (!(vma->vm_flags & VM_MAYSHARE))
794 795 796 797
		vma->vm_private_data = (void *)0;
}

/* Returns true if the VMA has associated reserve pages */
798
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
799
{
800 801 802 803 804 805 806 807 808 809 810
	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)
811
			return true;
812
		else
813
			return false;
814
	}
815 816

	/* Shared mappings always use reserves */
817 818 819 820 821 822 823 824 825 826 827 828 829
	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;
	}
830 831 832 833 834

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855
	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;
	}
856

857
	return false;
858 859
}

860
static void enqueue_huge_page(struct hstate *h, struct page *page)
L
Linus Torvalds 已提交
861 862
{
	int nid = page_to_nid(page);
863
	list_move(&page->lru, &h->hugepage_freelists[nid]);
864 865
	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
L
Linus Torvalds 已提交
866 867
}

868 869 870 871
static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
{
	struct page *page;

872 873 874 875 876 877 878 879
	list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
		if (!is_migrate_isolate_page(page))
			break;
	/*
	 * if 'non-isolated free hugepage' not found on the list,
	 * the allocation fails.
	 */
	if (&h->hugepage_freelists[nid] == &page->lru)
880
		return NULL;
881
	list_move(&page->lru, &h->hugepage_activelist);
882
	set_page_refcounted(page);
883 884 885 886 887
	h->free_huge_pages--;
	h->free_huge_pages_node[nid]--;
	return page;
}

888 889 890
/* Movability of hugepages depends on migration support. */
static inline gfp_t htlb_alloc_mask(struct hstate *h)
{
891
	if (hugepages_treat_as_movable || hugepage_migration_supported(h))
892 893 894 895 896
		return GFP_HIGHUSER_MOVABLE;
	else
		return GFP_HIGHUSER;
}

897 898
static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
899 900
				unsigned long address, int avoid_reserve,
				long chg)
L
Linus Torvalds 已提交
901
{
902
	struct page *page = NULL;
903
	struct mempolicy *mpol;
904
	nodemask_t *nodemask;
905
	struct zonelist *zonelist;
906 907
	struct zone *zone;
	struct zoneref *z;
908
	unsigned int cpuset_mems_cookie;
L
Linus Torvalds 已提交
909

910 911 912 913 914
	/*
	 * 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
	 */
915
	if (!vma_has_reserves(vma, chg) &&
916
			h->free_huge_pages - h->resv_huge_pages == 0)
917
		goto err;
918

919
	/* If reserves cannot be used, ensure enough pages are in the pool */
920
	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
921
		goto err;
922

923
retry_cpuset:
924
	cpuset_mems_cookie = read_mems_allowed_begin();
925
	zonelist = huge_zonelist(vma, address,
926
					htlb_alloc_mask(h), &mpol, &nodemask);
927

928 929
	for_each_zone_zonelist_nodemask(zone, z, zonelist,
						MAX_NR_ZONES - 1, nodemask) {
930
		if (cpuset_zone_allowed(zone, htlb_alloc_mask(h))) {
931 932
			page = dequeue_huge_page_node(h, zone_to_nid(zone));
			if (page) {
933 934 935 936 937
				if (avoid_reserve)
					break;
				if (!vma_has_reserves(vma, chg))
					break;

938
				SetPagePrivate(page);
939
				h->resv_huge_pages--;
940 941
				break;
			}
A
Andrew Morton 已提交
942
		}
L
Linus Torvalds 已提交
943
	}
944

945
	mpol_cond_put(mpol);
946
	if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
947
		goto retry_cpuset;
L
Linus Torvalds 已提交
948
	return page;
949 950 951

err:
	return NULL;
L
Linus Torvalds 已提交
952 953
}

954 955 956 957 958 959 960 961 962
/*
 * 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)
{
963
	nid = next_node_in(nid, *nodes_allowed);
964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024
	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--)

1025 1026 1027
#if (defined(CONFIG_X86_64) || defined(CONFIG_S390)) && \
	((defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || \
	defined(CONFIG_CMA))
1028
static void destroy_compound_gigantic_page(struct page *page,
1029
					unsigned int order)
1030 1031 1032 1033 1034
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

1035
	atomic_set(compound_mapcount_ptr(page), 0);
1036
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1037
		clear_compound_head(p);
1038 1039 1040 1041 1042 1043 1044
		set_page_refcounted(p);
	}

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

1045
static void free_gigantic_page(struct page *page, unsigned int order)
1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056
{
	free_contig_range(page_to_pfn(page), 1 << order);
}

static int __alloc_gigantic_page(unsigned long start_pfn,
				unsigned long nr_pages)
{
	unsigned long end_pfn = start_pfn + nr_pages;
	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
}

1057 1058
static bool pfn_range_valid_gigantic(struct zone *z,
			unsigned long start_pfn, unsigned long nr_pages)
1059 1060 1061 1062 1063 1064 1065 1066 1067 1068
{
	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);

1069 1070 1071
		if (page_zone(page) != z)
			return false;

1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091
		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);
}

1092
static struct page *alloc_gigantic_page(int nid, unsigned int order)
1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103
{
	unsigned long nr_pages = 1 << order;
	unsigned long ret, pfn, flags;
	struct zone *z;

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

		pfn = ALIGN(z->zone_start_pfn, nr_pages);
		while (zone_spans_last_pfn(z, pfn, nr_pages)) {
1104
			if (pfn_range_valid_gigantic(z, pfn, nr_pages)) {
1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 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...
				 */
				spin_unlock_irqrestore(&z->lock, flags);
				ret = __alloc_gigantic_page(pfn, nr_pages);
				if (!ret)
					return pfn_to_page(pfn);
				spin_lock_irqsave(&z->lock, flags);
			}
			pfn += nr_pages;
		}

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

	return NULL;
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1128
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160

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

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

	return page;
}

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

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

	return 0;
}

static inline bool gigantic_page_supported(void) { return true; }
#else
static inline bool gigantic_page_supported(void) { return false; }
1161
static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1162
static inline void destroy_compound_gigantic_page(struct page *page,
1163
						unsigned int order) { }
1164 1165 1166 1167
static inline int alloc_fresh_gigantic_page(struct hstate *h,
					nodemask_t *nodes_allowed) { return 0; }
#endif

1168
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1169 1170
{
	int i;
1171

1172 1173
	if (hstate_is_gigantic(h) && !gigantic_page_supported())
		return;
1174

1175 1176 1177
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
1178 1179
		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
1180 1181
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1182
	}
1183
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1184
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1185
	set_page_refcounted(page);
1186 1187 1188 1189 1190 1191
	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
1192 1193
}

1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204
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;
}

1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229
/*
 * 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]);
}

1230
void free_huge_page(struct page *page)
1231
{
1232 1233 1234 1235
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1236
	struct hstate *h = page_hstate(page);
1237
	int nid = page_to_nid(page);
1238 1239
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1240
	bool restore_reserve;
1241

1242
	set_page_private(page, 0);
1243
	page->mapping = NULL;
1244 1245
	VM_BUG_ON_PAGE(page_count(page), page);
	VM_BUG_ON_PAGE(page_mapcount(page), page);
1246
	restore_reserve = PagePrivate(page);
1247
	ClearPagePrivate(page);
1248

1249 1250 1251 1252 1253 1254 1255 1256
	/*
	 * 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;

1257
	spin_lock(&hugetlb_lock);
1258
	clear_page_huge_active(page);
1259 1260
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1261 1262 1263
	if (restore_reserve)
		h->resv_huge_pages++;

1264
	if (h->surplus_huge_pages_node[nid]) {
1265 1266
		/* remove the page from active list */
		list_del(&page->lru);
1267 1268 1269
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1270
	} else {
1271
		arch_clear_hugepage_flags(page);
1272
		enqueue_huge_page(h, page);
1273
	}
1274 1275 1276
	spin_unlock(&hugetlb_lock);
}

1277
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1278
{
1279
	INIT_LIST_HEAD(&page->lru);
1280
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1281
	spin_lock(&hugetlb_lock);
1282
	set_hugetlb_cgroup(page, NULL);
1283 1284
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1285 1286 1287 1288
	spin_unlock(&hugetlb_lock);
	put_page(page); /* free it into the hugepage allocator */
}

1289
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1290 1291 1292 1293 1294 1295 1296
{
	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);
1297
	__ClearPageReserved(page);
1298
	__SetPageHead(page);
1299
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312
		/*
		 * 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);
1313
		set_page_count(p, 0);
1314
		set_compound_head(p, page);
1315
	}
1316
	atomic_set(compound_mapcount_ptr(page), -1);
1317 1318
}

A
Andrew Morton 已提交
1319 1320 1321 1322 1323
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1324 1325 1326 1327 1328 1329
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1330
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1331
}
1332 1333
EXPORT_SYMBOL_GPL(PageHuge);

1334 1335 1336 1337 1338 1339 1340 1341 1342
/*
 * 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;

1343
	return get_compound_page_dtor(page_head) == free_huge_page;
1344 1345
}

1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
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;
}

1363
static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
L
Linus Torvalds 已提交
1364 1365
{
	struct page *page;
1366

1367
	page = __alloc_pages_node(nid,
1368
		htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
1369
						__GFP_REPEAT|__GFP_NOWARN,
1370
		huge_page_order(h));
L
Linus Torvalds 已提交
1371
	if (page) {
1372
		prep_new_huge_page(h, page, nid);
L
Linus Torvalds 已提交
1373
	}
1374 1375 1376 1377

	return page;
}

1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399
static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
{
	struct page *page;
	int nr_nodes, node;
	int ret = 0;

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

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

	return ret;
}

1400 1401 1402 1403 1404 1405
/*
 * 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.
 */
1406 1407
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1408
{
1409
	int nr_nodes, node;
1410 1411
	int ret = 0;

1412
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1413 1414 1415 1416
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1417 1418
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1419
			struct page *page =
1420
				list_entry(h->hugepage_freelists[node].next,
1421 1422 1423
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1424
			h->free_huge_pages_node[node]--;
1425 1426
			if (acct_surplus) {
				h->surplus_huge_pages--;
1427
				h->surplus_huge_pages_node[node]--;
1428
			}
1429 1430
			update_and_free_page(h, page);
			ret = 1;
1431
			break;
1432
		}
1433
	}
1434 1435 1436 1437

	return ret;
}

1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
 * nothing for in-use (including surplus) hugepages.
 */
static void dissolve_free_huge_page(struct page *page)
{
	spin_lock(&hugetlb_lock);
	if (PageHuge(page) && !page_count(page)) {
		struct hstate *h = page_hstate(page);
		int nid = page_to_nid(page);
		list_del(&page->lru);
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
1451
		h->max_huge_pages--;
1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465
		update_and_free_page(h, page);
	}
	spin_unlock(&hugetlb_lock);
}

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

1466 1467 1468
	if (!hugepages_supported())
		return;

1469 1470
	VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << minimum_order));
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order)
1471 1472 1473
		dissolve_free_huge_page(pfn_to_page(pfn));
}

1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491
/*
 * There are 3 ways this can get called:
 * 1. With vma+addr: we use the VMA's memory policy
 * 2. With !vma, but nid=NUMA_NO_NODE:  We try to allocate a huge
 *    page from any node, and let the buddy allocator itself figure
 *    it out.
 * 3. With !vma, but nid!=NUMA_NO_NODE.  We allocate a huge page
 *    strictly from 'nid'
 */
static struct page *__hugetlb_alloc_buddy_huge_page(struct hstate *h,
		struct vm_area_struct *vma, unsigned long addr, int nid)
{
	int order = huge_page_order(h);
	gfp_t gfp = htlb_alloc_mask(h)|__GFP_COMP|__GFP_REPEAT|__GFP_NOWARN;
	unsigned int cpuset_mems_cookie;

	/*
	 * We need a VMA to get a memory policy.  If we do not
D
Dave Hansen 已提交
1492 1493 1494 1495 1496 1497
	 * have one, we use the 'nid' argument.
	 *
	 * The mempolicy stuff below has some non-inlined bits
	 * and calls ->vm_ops.  That makes it hard to optimize at
	 * compile-time, even when NUMA is off and it does
	 * nothing.  This helps the compiler optimize it out.
1498
	 */
D
Dave Hansen 已提交
1499
	if (!IS_ENABLED(CONFIG_NUMA) || !vma) {
1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515
		/*
		 * If a specific node is requested, make sure to
		 * get memory from there, but only when a node
		 * is explicitly specified.
		 */
		if (nid != NUMA_NO_NODE)
			gfp |= __GFP_THISNODE;
		/*
		 * Make sure to call something that can handle
		 * nid=NUMA_NO_NODE
		 */
		return alloc_pages_node(nid, gfp, order);
	}

	/*
	 * OK, so we have a VMA.  Fetch the mempolicy and try to
D
Dave Hansen 已提交
1516 1517
	 * allocate a huge page with it.  We will only reach this
	 * when CONFIG_NUMA=y.
1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549
	 */
	do {
		struct page *page;
		struct mempolicy *mpol;
		struct zonelist *zl;
		nodemask_t *nodemask;

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

	return NULL;
}

/*
 * There are two ways to allocate a huge page:
 * 1. When you have a VMA and an address (like a fault)
 * 2. When you have no VMA (like when setting /proc/.../nr_hugepages)
 *
 * 'vma' and 'addr' are only for (1).  'nid' is always NUMA_NO_NODE in
 * this case which signifies that the allocation should be done with
 * respect for the VMA's memory policy.
 *
 * For (2), we ignore 'vma' and 'addr' and use 'nid' exclusively. This
 * implies that memory policies will not be taken in to account.
 */
static struct page *__alloc_buddy_huge_page(struct hstate *h,
		struct vm_area_struct *vma, unsigned long addr, int nid)
1550 1551
{
	struct page *page;
1552
	unsigned int r_nid;
1553

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

1557 1558 1559 1560 1561 1562
	/*
	 * Make sure that anyone specifying 'nid' is not also specifying a VMA.
	 * This makes sure the caller is picking _one_ of the modes with which
	 * we can call this function, not both.
	 */
	if (vma || (addr != -1)) {
D
Dave Hansen 已提交
1563 1564
		VM_WARN_ON_ONCE(addr == -1);
		VM_WARN_ON_ONCE(nid != NUMA_NO_NODE);
1565
	}
1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589
	/*
	 * Assume we will successfully allocate the surplus page to
	 * prevent racing processes from causing the surplus to exceed
	 * overcommit
	 *
	 * This however introduces a different race, where a process B
	 * tries to grow the static hugepage pool while alloc_pages() is
	 * called by process A. B will only examine the per-node
	 * counters in determining if surplus huge pages can be
	 * converted to normal huge pages in adjust_pool_surplus(). A
	 * won't be able to increment the per-node counter, until the
	 * lock is dropped by B, but B doesn't drop hugetlb_lock until
	 * no more huge pages can be converted from surplus to normal
	 * state (and doesn't try to convert again). Thus, we have a
	 * case where a surplus huge page exists, the pool is grown, and
	 * the surplus huge page still exists after, even though it
	 * should just have been converted to a normal huge page. This
	 * does not leak memory, though, as the hugepage will be freed
	 * once it is out of use. It also does not allow the counters to
	 * go out of whack in adjust_pool_surplus() as we don't modify
	 * the node values until we've gotten the hugepage and only the
	 * per-node value is checked there.
	 */
	spin_lock(&hugetlb_lock);
1590
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
1591 1592 1593
		spin_unlock(&hugetlb_lock);
		return NULL;
	} else {
1594 1595
		h->nr_huge_pages++;
		h->surplus_huge_pages++;
1596 1597 1598
	}
	spin_unlock(&hugetlb_lock);

1599
	page = __hugetlb_alloc_buddy_huge_page(h, vma, addr, nid);
1600 1601

	spin_lock(&hugetlb_lock);
1602
	if (page) {
1603
		INIT_LIST_HEAD(&page->lru);
1604
		r_nid = page_to_nid(page);
1605
		set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1606
		set_hugetlb_cgroup(page, NULL);
1607 1608 1609
		/*
		 * We incremented the global counters already
		 */
1610 1611
		h->nr_huge_pages_node[r_nid]++;
		h->surplus_huge_pages_node[r_nid]++;
1612
		__count_vm_event(HTLB_BUDDY_PGALLOC);
1613
	} else {
1614 1615
		h->nr_huge_pages--;
		h->surplus_huge_pages--;
1616
		__count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1617
	}
1618
	spin_unlock(&hugetlb_lock);
1619 1620 1621 1622

	return page;
}

1623 1624 1625 1626 1627
/*
 * Allocate a huge page from 'nid'.  Note, 'nid' may be
 * NUMA_NO_NODE, which means that it may be allocated
 * anywhere.
 */
D
Dave Hansen 已提交
1628
static
1629 1630 1631 1632 1633 1634 1635 1636 1637 1638
struct page *__alloc_buddy_huge_page_no_mpol(struct hstate *h, int nid)
{
	unsigned long addr = -1;

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

/*
 * Use the VMA's mpolicy to allocate a huge page from the buddy.
 */
D
Dave Hansen 已提交
1639
static
1640 1641 1642 1643 1644 1645
struct page *__alloc_buddy_huge_page_with_mpol(struct hstate *h,
		struct vm_area_struct *vma, unsigned long addr)
{
	return __alloc_buddy_huge_page(h, vma, addr, NUMA_NO_NODE);
}

1646 1647 1648 1649 1650 1651 1652
/*
 * This allocation function is useful in the context where vma is irrelevant.
 * E.g. soft-offlining uses this function because it only cares physical
 * address of error page.
 */
struct page *alloc_huge_page_node(struct hstate *h, int nid)
{
1653
	struct page *page = NULL;
1654 1655

	spin_lock(&hugetlb_lock);
1656 1657
	if (h->free_huge_pages - h->resv_huge_pages > 0)
		page = dequeue_huge_page_node(h, nid);
1658 1659
	spin_unlock(&hugetlb_lock);

1660
	if (!page)
1661
		page = __alloc_buddy_huge_page_no_mpol(h, nid);
1662 1663 1664 1665

	return page;
}

1666
/*
L
Lucas De Marchi 已提交
1667
 * Increase the hugetlb pool such that it can accommodate a reservation
1668 1669
 * of size 'delta'.
 */
1670
static int gather_surplus_pages(struct hstate *h, int delta)
1671 1672 1673 1674 1675
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
1676
	bool alloc_ok = true;
1677

1678
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1679
	if (needed <= 0) {
1680
		h->resv_huge_pages += delta;
1681
		return 0;
1682
	}
1683 1684 1685 1686 1687 1688 1689 1690

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
1691
		page = __alloc_buddy_huge_page_no_mpol(h, NUMA_NO_NODE);
1692 1693 1694 1695
		if (!page) {
			alloc_ok = false;
			break;
		}
1696 1697
		list_add(&page->lru, &surplus_list);
	}
1698
	allocated += i;
1699 1700 1701 1702 1703 1704

	/*
	 * 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);
1705 1706
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
1707 1708 1709 1710 1711 1712 1713 1714 1715 1716
	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;
	}
1717 1718
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
1719
	 * needed to accommodate the reservation.  Add the appropriate number
1720
	 * of pages to the hugetlb pool and free the extras back to the buddy
1721 1722 1723
	 * 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.
1724 1725
	 */
	needed += allocated;
1726
	h->resv_huge_pages += delta;
1727
	ret = 0;
1728

1729
	/* Free the needed pages to the hugetlb pool */
1730
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1731 1732
		if ((--needed) < 0)
			break;
1733 1734 1735 1736 1737
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
1738
		VM_BUG_ON_PAGE(page_count(page), page);
1739
		enqueue_huge_page(h, page);
1740
	}
1741
free:
1742
	spin_unlock(&hugetlb_lock);
1743 1744

	/* Free unnecessary surplus pages to the buddy allocator */
1745 1746
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
1747
	spin_lock(&hugetlb_lock);
1748 1749 1750 1751 1752 1753 1754 1755

	return ret;
}

/*
 * When releasing a hugetlb pool reservation, any surplus pages that were
 * allocated to satisfy the reservation must be explicitly freed if they were
 * never used.
1756
 * Called with hugetlb_lock held.
1757
 */
1758 1759
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
1760 1761 1762
{
	unsigned long nr_pages;

1763
	/* Uncommit the reservation */
1764
	h->resv_huge_pages -= unused_resv_pages;
1765

1766
	/* Cannot return gigantic pages currently */
1767
	if (hstate_is_gigantic(h))
1768 1769
		return;

1770
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1771

1772 1773
	/*
	 * We want to release as many surplus pages as possible, spread
1774 1775 1776 1777 1778
	 * 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.
1779 1780
	 */
	while (nr_pages--) {
1781
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1782
			break;
1783
		cond_resched_lock(&hugetlb_lock);
1784 1785 1786
	}
}

1787

1788
/*
1789
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1790
 * are used by the huge page allocation routines to manage reservations.
1791 1792 1793 1794 1795 1796
 *
 * 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
1797 1798 1799
 * 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.
1800 1801 1802 1803 1804 1805
 *
 * 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.
1806
 */
1807 1808 1809
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
1810
	VMA_END_RESV,
1811
};
1812 1813
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
1814
				enum vma_resv_mode mode)
1815
{
1816 1817
	struct resv_map *resv;
	pgoff_t idx;
1818
	long ret;
1819

1820 1821
	resv = vma_resv_map(vma);
	if (!resv)
1822
		return 1;
1823

1824
	idx = vma_hugecache_offset(h, vma, addr);
1825 1826
	switch (mode) {
	case VMA_NEEDS_RESV:
1827
		ret = region_chg(resv, idx, idx + 1);
1828 1829 1830 1831
		break;
	case VMA_COMMIT_RESV:
		ret = region_add(resv, idx, idx + 1);
		break;
1832
	case VMA_END_RESV:
1833 1834 1835 1836 1837 1838
		region_abort(resv, idx, idx + 1);
		ret = 0;
		break;
	default:
		BUG();
	}
1839

1840
	if (vma->vm_flags & VM_MAYSHARE)
1841
		return ret;
1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860
	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;
	}
1861
	else
1862
		return ret < 0 ? ret : 0;
1863
}
1864 1865

static long vma_needs_reservation(struct hstate *h,
1866
			struct vm_area_struct *vma, unsigned long addr)
1867
{
1868
	return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
1869
}
1870

1871 1872 1873
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
1874 1875 1876
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

1877
static void vma_end_reservation(struct hstate *h,
1878 1879
			struct vm_area_struct *vma, unsigned long addr)
{
1880
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
1881 1882
}

1883
struct page *alloc_huge_page(struct vm_area_struct *vma,
1884
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
1885
{
1886
	struct hugepage_subpool *spool = subpool_vma(vma);
1887
	struct hstate *h = hstate_vma(vma);
1888
	struct page *page;
1889 1890
	long map_chg, map_commit;
	long gbl_chg;
1891 1892
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
1893

1894
	idx = hstate_index(h);
1895
	/*
1896 1897 1898
	 * 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).
1899
	 */
1900 1901
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
1902
		return ERR_PTR(-ENOMEM);
1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913

	/*
	 * 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) {
1914
			vma_end_reservation(h, vma, addr);
1915
			return ERR_PTR(-ENOSPC);
1916
		}
L
Linus Torvalds 已提交
1917

1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929
		/*
		 * 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;
	}

1930
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
1931 1932 1933
	if (ret)
		goto out_subpool_put;

L
Linus Torvalds 已提交
1934
	spin_lock(&hugetlb_lock);
1935 1936 1937 1938 1939 1940
	/*
	 * 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);
1941
	if (!page) {
1942
		spin_unlock(&hugetlb_lock);
1943
		page = __alloc_buddy_huge_page_with_mpol(h, vma, addr);
1944 1945
		if (!page)
			goto out_uncharge_cgroup;
1946 1947 1948 1949
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
1950 1951
		spin_lock(&hugetlb_lock);
		list_move(&page->lru, &h->hugepage_activelist);
1952
		/* Fall through */
K
Ken Chen 已提交
1953
	}
1954 1955
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
	spin_unlock(&hugetlb_lock);
1956

1957
	set_page_private(page, (unsigned long)spool);
1958

1959 1960
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974
		/*
		 * 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);
	}
1975
	return page;
1976 1977 1978 1979

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
out_subpool_put:
1980
	if (map_chg || avoid_reserve)
1981
		hugepage_subpool_put_pages(spool, 1);
1982
	vma_end_reservation(h, vma, addr);
1983
	return ERR_PTR(-ENOSPC);
1984 1985
}

1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999
/*
 * alloc_huge_page()'s wrapper which simply returns the page if allocation
 * succeeds, otherwise NULL. This function is called from new_vma_page(),
 * where no ERR_VALUE is expected to be returned.
 */
struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
				unsigned long addr, int avoid_reserve)
{
	struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
	if (IS_ERR(page))
		page = NULL;
	return page;
}

2000
int __weak alloc_bootmem_huge_page(struct hstate *h)
2001 2002
{
	struct huge_bootmem_page *m;
2003
	int nr_nodes, node;
2004

2005
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2006 2007
		void *addr;

2008 2009 2010
		addr = memblock_virt_alloc_try_nid_nopanic(
				huge_page_size(h), huge_page_size(h),
				0, BOOTMEM_ALLOC_ACCESSIBLE, node);
2011 2012 2013 2014 2015 2016 2017
		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;
2018
			goto found;
2019 2020 2021 2022 2023
		}
	}
	return 0;

found:
2024
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2025 2026 2027 2028 2029 2030
	/* 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;
}

2031 2032
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
2033 2034 2035 2036 2037 2038 2039
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

2040 2041 2042 2043 2044 2045 2046
/* 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;
2047 2048 2049 2050
		struct page *page;

#ifdef CONFIG_HIGHMEM
		page = pfn_to_page(m->phys >> PAGE_SHIFT);
2051 2052
		memblock_free_late(__pa(m),
				   sizeof(struct huge_bootmem_page));
2053 2054 2055
#else
		page = virt_to_page(m);
#endif
2056
		WARN_ON(page_count(page) != 1);
2057
		prep_compound_huge_page(page, h->order);
2058
		WARN_ON(PageReserved(page));
2059
		prep_new_huge_page(h, page, page_to_nid(page));
2060 2061 2062 2063 2064 2065
		/*
		 * 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.
		 */
2066
		if (hstate_is_gigantic(h))
2067
			adjust_managed_page_count(page, 1 << h->order);
2068 2069 2070
	}
}

2071
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2072 2073
{
	unsigned long i;
2074

2075
	for (i = 0; i < h->max_huge_pages; ++i) {
2076
		if (hstate_is_gigantic(h)) {
2077 2078
			if (!alloc_bootmem_huge_page(h))
				break;
2079
		} else if (!alloc_fresh_huge_page(h,
2080
					 &node_states[N_MEMORY]))
L
Linus Torvalds 已提交
2081 2082
			break;
	}
2083
	h->max_huge_pages = i;
2084 2085 2086 2087 2088 2089 2090
}

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

	for_each_hstate(h) {
2091 2092 2093
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2094
		/* oversize hugepages were init'ed in early boot */
2095
		if (!hstate_is_gigantic(h))
2096
			hugetlb_hstate_alloc_pages(h);
2097
	}
2098
	VM_BUG_ON(minimum_order == UINT_MAX);
2099 2100
}

A
Andi Kleen 已提交
2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111
static char * __init memfmt(char *buf, unsigned long n)
{
	if (n >= (1UL << 30))
		sprintf(buf, "%lu GB", n >> 30);
	else if (n >= (1UL << 20))
		sprintf(buf, "%lu MB", n >> 20);
	else
		sprintf(buf, "%lu KB", n >> 10);
	return buf;
}

2112 2113 2114 2115 2116
static void __init report_hugepages(void)
{
	struct hstate *h;

	for_each_hstate(h) {
A
Andi Kleen 已提交
2117
		char buf[32];
2118
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
A
Andi Kleen 已提交
2119 2120
			memfmt(buf, huge_page_size(h)),
			h->free_huge_pages);
2121 2122 2123
	}
}

L
Linus Torvalds 已提交
2124
#ifdef CONFIG_HIGHMEM
2125 2126
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2127
{
2128 2129
	int i;

2130
	if (hstate_is_gigantic(h))
2131 2132
		return;

2133
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2134
		struct page *page, *next;
2135 2136 2137
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2138
				return;
L
Linus Torvalds 已提交
2139 2140 2141
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2142
			update_and_free_page(h, page);
2143 2144
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2145 2146 2147 2148
		}
	}
}
#else
2149 2150
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2151 2152 2153 2154
{
}
#endif

2155 2156 2157 2158 2159
/*
 * 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.
 */
2160 2161
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2162
{
2163
	int nr_nodes, node;
2164 2165 2166

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

2167 2168 2169 2170
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2171
		}
2172 2173 2174 2175 2176
	} 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;
2177
		}
2178 2179
	}
	return 0;
2180

2181 2182 2183 2184
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2185 2186
}

2187
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2188 2189
static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2190
{
2191
	unsigned long min_count, ret;
L
Linus Torvalds 已提交
2192

2193
	if (hstate_is_gigantic(h) && !gigantic_page_supported())
2194 2195
		return h->max_huge_pages;

2196 2197 2198 2199
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2200
	 *
N
Naoya Horiguchi 已提交
2201
	 * We might race with __alloc_buddy_huge_page() here and be unable
2202 2203 2204 2205
	 * 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.
2206
	 */
L
Linus Torvalds 已提交
2207
	spin_lock(&hugetlb_lock);
2208
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2209
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2210 2211 2212
			break;
	}

2213
	while (count > persistent_huge_pages(h)) {
2214 2215 2216 2217 2218 2219
		/*
		 * 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);
2220 2221 2222 2223

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

2224 2225 2226 2227
		if (hstate_is_gigantic(h))
			ret = alloc_fresh_gigantic_page(h, nodes_allowed);
		else
			ret = alloc_fresh_huge_page(h, nodes_allowed);
2228 2229 2230 2231
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2232 2233 2234
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2235 2236 2237 2238 2239 2240 2241 2242
	}

	/*
	 * 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.
2243 2244 2245 2246
	 *
	 * By placing pages into the surplus state independent of the
	 * overcommit value, we are allowing the surplus pool size to
	 * exceed overcommit. There are few sane options here. Since
N
Naoya Horiguchi 已提交
2247
	 * __alloc_buddy_huge_page() is checking the global counter,
2248 2249 2250
	 * 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.
2251
	 */
2252
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2253
	min_count = max(count, min_count);
2254
	try_to_free_low(h, min_count, nodes_allowed);
2255
	while (min_count < persistent_huge_pages(h)) {
2256
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2257
			break;
2258
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2259
	}
2260
	while (count < persistent_huge_pages(h)) {
2261
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2262 2263 2264
			break;
	}
out:
2265
	ret = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2266
	spin_unlock(&hugetlb_lock);
2267
	return ret;
L
Linus Torvalds 已提交
2268 2269
}

2270 2271 2272 2273 2274 2275 2276 2277 2278 2279
#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];

2280 2281 2282
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2283 2284
{
	int i;
2285

2286
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2287 2288 2289
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2290
			return &hstates[i];
2291 2292 2293
		}

	return kobj_to_node_hstate(kobj, nidp);
2294 2295
}

2296
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2297 2298
					struct kobj_attribute *attr, char *buf)
{
2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309
	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);
2310
}
2311

2312 2313 2314
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2315 2316
{
	int err;
2317
	NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
2318

2319
	if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
2320 2321 2322 2323
		err = -EINVAL;
		goto out;
	}

2324 2325 2326 2327 2328 2329 2330
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
				init_nodemask_of_mempolicy(nodes_allowed))) {
			NODEMASK_FREE(nodes_allowed);
2331
			nodes_allowed = &node_states[N_MEMORY];
2332 2333 2334 2335 2336 2337 2338 2339 2340
		}
	} 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
2341
		nodes_allowed = &node_states[N_MEMORY];
2342

2343
	h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
2344

2345
	if (nodes_allowed != &node_states[N_MEMORY])
2346 2347 2348
		NODEMASK_FREE(nodes_allowed);

	return len;
2349 2350 2351
out:
	NODEMASK_FREE(nodes_allowed);
	return err;
2352 2353
}

2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370
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);
}

2371 2372 2373 2374 2375 2376 2377 2378 2379
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)
{
2380
	return nr_hugepages_store_common(false, kobj, buf, len);
2381 2382 2383
}
HSTATE_ATTR(nr_hugepages);

2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398
#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)
{
2399
	return nr_hugepages_store_common(true, kobj, buf, len);
2400 2401 2402 2403 2404
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2405 2406 2407
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2408
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2409 2410
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2411

2412 2413 2414 2415 2416
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;
2417
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2418

2419
	if (hstate_is_gigantic(h))
2420 2421
		return -EINVAL;

2422
	err = kstrtoul(buf, 10, &input);
2423
	if (err)
2424
		return err;
2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436

	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)
{
2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447
	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);
2448 2449 2450 2451 2452 2453
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2454
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2455 2456 2457 2458 2459 2460 2461
	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)
{
2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472
	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);
2473 2474 2475 2476 2477 2478 2479 2480 2481
}
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,
2482 2483 2484
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
2485 2486 2487 2488 2489 2490 2491
	NULL,
};

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

J
Jeff Mahoney 已提交
2492 2493 2494
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
				    struct attribute_group *hstate_attr_group)
2495 2496
{
	int retval;
2497
	int hi = hstate_index(h);
2498

2499 2500
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
2501 2502
		return -ENOMEM;

2503
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2504
	if (retval)
2505
		kobject_put(hstate_kobjs[hi]);
2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519

	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) {
2520 2521
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
2522
		if (err)
2523
			pr_err("Hugetlb: Unable to add hstate %s", h->name);
2524 2525 2526
	}
}

2527 2528 2529 2530
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2531 2532 2533
 * 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
2534 2535 2536 2537 2538 2539
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
2540
static struct node_hstate node_hstates[MAX_NUMNODES];
2541 2542

/*
2543
 * A subset of global hstate attributes for node devices
2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556
 */
static struct attribute *per_node_hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
	NULL,
};

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

/*
2557
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579
 * 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;
}

/*
2580
 * Unregister hstate attributes from a single node device.
2581 2582
 * No-op if no hstate attributes attached.
 */
2583
static void hugetlb_unregister_node(struct node *node)
2584 2585
{
	struct hstate *h;
2586
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2587 2588

	if (!nhs->hugepages_kobj)
2589
		return;		/* no hstate attributes */
2590

2591 2592 2593 2594 2595
	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;
2596
		}
2597
	}
2598 2599 2600 2601 2602 2603 2604

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


/*
2605
 * Register hstate attributes for a single node device.
2606 2607
 * No-op if attributes already registered.
 */
2608
static void hugetlb_register_node(struct node *node)
2609 2610
{
	struct hstate *h;
2611
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2612 2613 2614 2615 2616 2617
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2618
							&node->dev.kobj);
2619 2620 2621 2622 2623 2624 2625 2626
	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) {
2627 2628
			pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
				h->name, node->dev.id);
2629 2630 2631 2632 2633 2634 2635
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
2636
 * hugetlb init time:  register hstate attributes for all registered node
2637 2638
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
2639
 */
2640
static void __init hugetlb_register_all_nodes(void)
2641 2642 2643
{
	int nid;

2644
	for_each_node_state(nid, N_MEMORY) {
2645
		struct node *node = node_devices[nid];
2646
		if (node->dev.id == nid)
2647 2648 2649 2650
			hugetlb_register_node(node);
	}

	/*
2651
	 * Let the node device driver know we're here so it can
2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670
	 * [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

2671 2672
static int __init hugetlb_init(void)
{
2673 2674
	int i;

2675
	if (!hugepages_supported())
2676
		return 0;
2677

2678 2679 2680 2681
	if (!size_to_hstate(default_hstate_size)) {
		default_hstate_size = HPAGE_SIZE;
		if (!size_to_hstate(default_hstate_size))
			hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
2682
	}
2683
	default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2684 2685 2686 2687
	if (default_hstate_max_huge_pages) {
		if (!default_hstate.max_huge_pages)
			default_hstate.max_huge_pages = default_hstate_max_huge_pages;
	}
2688 2689

	hugetlb_init_hstates();
2690
	gather_bootmem_prealloc();
2691 2692 2693
	report_hugepages();

	hugetlb_sysfs_init();
2694
	hugetlb_register_all_nodes();
2695
	hugetlb_cgroup_file_init();
2696

2697 2698 2699 2700 2701
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
2702
	hugetlb_fault_mutex_table =
2703
		kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
2704
	BUG_ON(!hugetlb_fault_mutex_table);
2705 2706

	for (i = 0; i < num_fault_mutexes; i++)
2707
		mutex_init(&hugetlb_fault_mutex_table[i]);
2708 2709
	return 0;
}
2710
subsys_initcall(hugetlb_init);
2711 2712

/* Should be called on processing a hugepagesz=... option */
2713 2714 2715 2716 2717
void __init hugetlb_bad_size(void)
{
	parsed_valid_hugepagesz = false;
}

2718
void __init hugetlb_add_hstate(unsigned int order)
2719 2720
{
	struct hstate *h;
2721 2722
	unsigned long i;

2723
	if (size_to_hstate(PAGE_SIZE << order)) {
J
Joe Perches 已提交
2724
		pr_warn("hugepagesz= specified twice, ignoring\n");
2725 2726
		return;
	}
2727
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2728
	BUG_ON(order == 0);
2729
	h = &hstates[hugetlb_max_hstate++];
2730 2731
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2732 2733 2734 2735
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2736
	INIT_LIST_HEAD(&h->hugepage_activelist);
2737 2738
	h->next_nid_to_alloc = first_memory_node;
	h->next_nid_to_free = first_memory_node;
2739 2740
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
2741

2742 2743 2744
	parsed_hstate = h;
}

2745
static int __init hugetlb_nrpages_setup(char *s)
2746 2747
{
	unsigned long *mhp;
2748
	static unsigned long *last_mhp;
2749

2750 2751 2752 2753 2754 2755
	if (!parsed_valid_hugepagesz) {
		pr_warn("hugepages = %s preceded by "
			"an unsupported hugepagesz, ignoring\n", s);
		parsed_valid_hugepagesz = true;
		return 1;
	}
2756
	/*
2757
	 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2758 2759
	 * so this hugepages= parameter goes to the "default hstate".
	 */
2760
	else if (!hugetlb_max_hstate)
2761 2762 2763 2764
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

2765
	if (mhp == last_mhp) {
J
Joe Perches 已提交
2766
		pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2767 2768 2769
		return 1;
	}

2770 2771 2772
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

2773 2774 2775 2776 2777
	/*
	 * 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.
	 */
2778
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2779 2780 2781 2782
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

2783 2784
	return 1;
}
2785 2786 2787 2788 2789 2790 2791 2792
__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);
2793

2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805
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
2806 2807 2808
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
2809
{
2810
	struct hstate *h = &default_hstate;
2811
	unsigned long tmp = h->max_huge_pages;
2812
	int ret;
2813

2814
	if (!hugepages_supported())
2815
		return -EOPNOTSUPP;
2816

2817 2818
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2819 2820 2821
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2822

2823 2824 2825
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
2826 2827
out:
	return ret;
L
Linus Torvalds 已提交
2828
}
2829

2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846
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 */

2847
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2848
			void __user *buffer,
2849 2850
			size_t *length, loff_t *ppos)
{
2851
	struct hstate *h = &default_hstate;
2852
	unsigned long tmp;
2853
	int ret;
2854

2855
	if (!hugepages_supported())
2856
		return -EOPNOTSUPP;
2857

2858
	tmp = h->nr_overcommit_huge_pages;
2859

2860
	if (write && hstate_is_gigantic(h))
2861 2862
		return -EINVAL;

2863 2864
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2865 2866 2867
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2868 2869 2870 2871 2872 2873

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
2874 2875
out:
	return ret;
2876 2877
}

L
Linus Torvalds 已提交
2878 2879
#endif /* CONFIG_SYSCTL */

2880
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
2881
{
2882
	struct hstate *h = &default_hstate;
2883 2884
	if (!hugepages_supported())
		return;
2885
	seq_printf(m,
2886 2887 2888 2889 2890
			"HugePages_Total:   %5lu\n"
			"HugePages_Free:    %5lu\n"
			"HugePages_Rsvd:    %5lu\n"
			"HugePages_Surp:    %5lu\n"
			"Hugepagesize:   %8lu kB\n",
2891 2892 2893 2894 2895
			h->nr_huge_pages,
			h->free_huge_pages,
			h->resv_huge_pages,
			h->surplus_huge_pages,
			1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
L
Linus Torvalds 已提交
2896 2897 2898 2899
}

int hugetlb_report_node_meminfo(int nid, char *buf)
{
2900
	struct hstate *h = &default_hstate;
2901 2902
	if (!hugepages_supported())
		return 0;
L
Linus Torvalds 已提交
2903 2904
	return sprintf(buf,
		"Node %d HugePages_Total: %5u\n"
2905 2906
		"Node %d HugePages_Free:  %5u\n"
		"Node %d HugePages_Surp:  %5u\n",
2907 2908 2909
		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
2910 2911
}

2912 2913 2914 2915 2916
void hugetlb_show_meminfo(void)
{
	struct hstate *h;
	int nid;

2917 2918 2919
	if (!hugepages_supported())
		return;

2920 2921 2922 2923 2924 2925 2926 2927 2928 2929
	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));
}

2930 2931 2932 2933 2934 2935
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
2936 2937 2938
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
2939 2940 2941 2942 2943 2944
	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
2945 2946
}

2947
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969
{
	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) {
2970
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
2971 2972
			goto out;

2973 2974
		if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
2975 2976 2977 2978 2979 2980
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
2981
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
2982 2983 2984 2985 2986 2987

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

2988 2989
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
2990
	struct resv_map *resv = vma_resv_map(vma);
2991 2992 2993 2994 2995

	/*
	 * 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
2996
	 * has a reference to the reservation map it cannot disappear until
2997 2998 2999
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
3000
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3001
		kref_get(&resv->refs);
3002 3003
}

3004 3005
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
3006
	struct hstate *h = hstate_vma(vma);
3007
	struct resv_map *resv = vma_resv_map(vma);
3008
	struct hugepage_subpool *spool = subpool_vma(vma);
3009
	unsigned long reserve, start, end;
3010
	long gbl_reserve;
3011

3012 3013
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
3014

3015 3016
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
3017

3018
	reserve = (end - start) - region_count(resv, start, end);
3019

3020 3021 3022
	kref_put(&resv->refs, resv_map_release);

	if (reserve) {
3023 3024 3025 3026 3027 3028
		/*
		 * 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);
3029
	}
3030 3031
}

L
Linus Torvalds 已提交
3032 3033 3034 3035 3036 3037
/*
 * We cannot handle pagefaults against hugetlb pages at all.  They cause
 * handle_mm_fault() to try to instantiate regular-sized pages in the
 * hugegpage VMA.  do_page_fault() is supposed to trap this, so BUG is we get
 * this far.
 */
N
Nick Piggin 已提交
3038
static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
L
Linus Torvalds 已提交
3039 3040
{
	BUG();
N
Nick Piggin 已提交
3041
	return 0;
L
Linus Torvalds 已提交
3042 3043
}

3044
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
3045
	.fault = hugetlb_vm_op_fault,
3046
	.open = hugetlb_vm_op_open,
3047
	.close = hugetlb_vm_op_close,
L
Linus Torvalds 已提交
3048 3049
};

3050 3051
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
3052 3053 3054
{
	pte_t entry;

3055
	if (writable) {
3056 3057
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
3058
	} else {
3059 3060
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
3061 3062 3063
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3064
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3065 3066 3067 3068

	return entry;
}

3069 3070 3071 3072 3073
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3074
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3075
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3076
		update_mmu_cache(vma, address, ptep);
3077 3078
}

3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103
static int is_hugetlb_entry_migration(pte_t pte)
{
	swp_entry_t swp;

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

static int is_hugetlb_entry_hwpoisoned(pte_t pte)
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
		return 0;
	swp = pte_to_swp_entry(pte);
	if (non_swap_entry(swp) && is_hwpoison_entry(swp))
		return 1;
	else
		return 0;
}
3104

D
David Gibson 已提交
3105 3106 3107 3108 3109
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;
3110
	unsigned long addr;
3111
	int cow;
3112 3113
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3114 3115 3116
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
	int ret = 0;
3117 3118

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3119

3120 3121 3122 3123 3124
	mmun_start = vma->vm_start;
	mmun_end = vma->vm_end;
	if (cow)
		mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);

3125
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3126
		spinlock_t *src_ptl, *dst_ptl;
H
Hugh Dickins 已提交
3127 3128 3129
		src_pte = huge_pte_offset(src, addr);
		if (!src_pte)
			continue;
3130
		dst_pte = huge_pte_alloc(dst, addr, sz);
3131 3132 3133 3134
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3135 3136 3137 3138 3139

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

3140 3141 3142
		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);
3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160
		entry = huge_ptep_get(src_pte);
		if (huge_pte_none(entry)) { /* skip none entry */
			;
		} else if (unlikely(is_hugetlb_entry_migration(entry) ||
				    is_hugetlb_entry_hwpoisoned(entry))) {
			swp_entry_t swp_entry = pte_to_swp_entry(entry);

			if (is_write_migration_entry(swp_entry) && cow) {
				/*
				 * COW mappings require pages in both
				 * parent and child to be set to read.
				 */
				make_migration_entry_read(&swp_entry);
				entry = swp_entry_to_pte(swp_entry);
				set_huge_pte_at(src, addr, src_pte, entry);
			}
			set_huge_pte_at(dst, addr, dst_pte, entry);
		} else {
3161
			if (cow) {
3162
				huge_ptep_set_wrprotect(src, addr, src_pte);
3163 3164 3165
				mmu_notifier_invalidate_range(src, mmun_start,
								   mmun_end);
			}
3166
			entry = huge_ptep_get(src_pte);
3167 3168
			ptepage = pte_page(entry);
			get_page(ptepage);
3169
			page_dup_rmap(ptepage, true);
3170
			set_huge_pte_at(dst, addr, dst_pte, entry);
3171
			hugetlb_count_add(pages_per_huge_page(h), dst);
3172
		}
3173 3174
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3175 3176
	}

3177 3178 3179 3180
	if (cow)
		mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);

	return ret;
D
David Gibson 已提交
3181 3182
}

3183 3184 3185
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
3186 3187 3188
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3189
	pte_t *ptep;
D
David Gibson 已提交
3190
	pte_t pte;
3191
	spinlock_t *ptl;
D
David Gibson 已提交
3192
	struct page *page;
3193 3194
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3195 3196
	const unsigned long mmun_start = start;	/* For mmu_notifiers */
	const unsigned long mmun_end   = end;	/* For mmu_notifiers */
3197

D
David Gibson 已提交
3198
	WARN_ON(!is_vm_hugetlb_page(vma));
3199 3200
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3201

3202
	tlb_start_vma(tlb, vma);
3203
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3204 3205
	address = start;
	for (; address < end; address += sz) {
3206
		ptep = huge_pte_offset(mm, address);
A
Adam Litke 已提交
3207
		if (!ptep)
3208 3209
			continue;

3210
		ptl = huge_pte_lock(h, mm, ptep);
3211 3212 3213 3214
		if (huge_pmd_unshare(mm, &address, ptep)) {
			spin_unlock(ptl);
			continue;
		}
3215

3216
		pte = huge_ptep_get(ptep);
3217 3218 3219 3220
		if (huge_pte_none(pte)) {
			spin_unlock(ptl);
			continue;
		}
3221 3222

		/*
3223 3224
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3225
		 */
3226
		if (unlikely(!pte_present(pte))) {
3227
			huge_pte_clear(mm, address, ptep);
3228 3229
			spin_unlock(ptl);
			continue;
3230
		}
3231 3232

		page = pte_page(pte);
3233 3234 3235 3236 3237 3238
		/*
		 * 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) {
3239 3240 3241 3242
			if (page != ref_page) {
				spin_unlock(ptl);
				continue;
			}
3243 3244 3245 3246 3247 3248 3249 3250
			/*
			 * 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);
		}

3251
		pte = huge_ptep_get_and_clear(mm, address, ptep);
3252
		tlb_remove_tlb_entry(tlb, ptep, address);
3253
		if (huge_pte_dirty(pte))
3254
			set_page_dirty(page);
3255

3256
		hugetlb_count_sub(pages_per_huge_page(h), mm);
3257
		page_remove_rmap(page, true);
3258

3259
		spin_unlock(ptl);
3260
		tlb_remove_page_size(tlb, page, huge_page_size(h));
3261 3262 3263 3264 3265
		/*
		 * Bail out after unmapping reference page if supplied
		 */
		if (ref_page)
			break;
3266
	}
3267
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3268
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
3269
}
D
David Gibson 已提交
3270

3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282
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
3283
	 * is to clear it before releasing the i_mmap_rwsem. This works
3284
	 * because in the context this is called, the VMA is about to be
3285
	 * destroyed and the i_mmap_rwsem is held.
3286 3287 3288 3289
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

3290
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3291
			  unsigned long end, struct page *ref_page)
3292
{
3293 3294 3295 3296 3297
	struct mm_struct *mm;
	struct mmu_gather tlb;

	mm = vma->vm_mm;

3298
	tlb_gather_mmu(&tlb, mm, start, end);
3299 3300
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
	tlb_finish_mmu(&tlb, start, end);
3301 3302
}

3303 3304 3305 3306 3307 3308
/*
 * 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.
 */
3309 3310
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
3311
{
3312
	struct hstate *h = hstate_vma(vma);
3313 3314 3315 3316 3317 3318 3319 3320
	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.
	 */
3321
	address = address & huge_page_mask(h);
3322 3323
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
3324
	mapping = vma->vm_file->f_mapping;
3325

3326 3327 3328 3329 3330
	/*
	 * 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
	 */
3331
	i_mmap_lock_write(mapping);
3332
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3333 3334 3335 3336
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

3337 3338 3339 3340 3341 3342 3343 3344
		/*
		 * 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;

3345 3346 3347 3348 3349 3350 3351 3352
		/*
		 * 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))
3353 3354
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
3355
	}
3356
	i_mmap_unlock_write(mapping);
3357 3358
}

3359 3360
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3361 3362 3363
 * 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.
3364
 */
3365
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3366
			unsigned long address, pte_t *ptep, pte_t pte,
3367
			struct page *pagecache_page, spinlock_t *ptl)
3368
{
3369
	struct hstate *h = hstate_vma(vma);
3370
	struct page *old_page, *new_page;
3371
	int ret = 0, outside_reserve = 0;
3372 3373
	unsigned long mmun_start;	/* For mmu_notifiers */
	unsigned long mmun_end;		/* For mmu_notifiers */
3374 3375 3376

	old_page = pte_page(pte);

3377
retry_avoidcopy:
3378 3379
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
3380
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3381
		page_move_anon_rmap(old_page, vma);
3382
		set_huge_ptep_writable(vma, address, ptep);
N
Nick Piggin 已提交
3383
		return 0;
3384 3385
	}

3386 3387 3388 3389 3390 3391 3392 3393 3394
	/*
	 * 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.
	 */
3395
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3396 3397 3398
			old_page != pagecache_page)
		outside_reserve = 1;

3399
	get_page(old_page);
3400

3401 3402 3403 3404
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
3405
	spin_unlock(ptl);
3406
	new_page = alloc_huge_page(vma, address, outside_reserve);
3407

3408
	if (IS_ERR(new_page)) {
3409 3410 3411 3412 3413 3414 3415 3416
		/*
		 * 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) {
3417
			put_page(old_page);
3418
			BUG_ON(huge_pte_none(pte));
3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430
			unmap_ref_private(mm, vma, old_page, address);
			BUG_ON(huge_pte_none(pte));
			spin_lock(ptl);
			ptep = huge_pte_offset(mm, address & huge_page_mask(h));
			if (likely(ptep &&
				   pte_same(huge_ptep_get(ptep), pte)))
				goto retry_avoidcopy;
			/*
			 * race occurs while re-acquiring page table
			 * lock, and our job is done.
			 */
			return 0;
3431 3432
		}

3433 3434 3435
		ret = (PTR_ERR(new_page) == -ENOMEM) ?
			VM_FAULT_OOM : VM_FAULT_SIGBUS;
		goto out_release_old;
3436 3437
	}

3438 3439 3440 3441
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
3442
	if (unlikely(anon_vma_prepare(vma))) {
3443 3444
		ret = VM_FAULT_OOM;
		goto out_release_all;
3445
	}
3446

A
Andrea Arcangeli 已提交
3447 3448
	copy_user_huge_page(new_page, old_page, address, vma,
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
3449
	__SetPageUptodate(new_page);
3450
	set_page_huge_active(new_page);
3451

3452 3453 3454
	mmun_start = address & huge_page_mask(h);
	mmun_end = mmun_start + huge_page_size(h);
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
3455

3456
	/*
3457
	 * Retake the page table lock to check for racing updates
3458 3459
	 * before the page tables are altered
	 */
3460
	spin_lock(ptl);
3461
	ptep = huge_pte_offset(mm, address & huge_page_mask(h));
3462
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3463 3464
		ClearPagePrivate(new_page);

3465
		/* Break COW */
3466
		huge_ptep_clear_flush(vma, address, ptep);
3467
		mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
3468 3469
		set_huge_pte_at(mm, address, ptep,
				make_huge_pte(vma, new_page, 1));
3470
		page_remove_rmap(old_page, true);
3471
		hugepage_add_new_anon_rmap(new_page, vma, address);
3472 3473 3474
		/* Make the old page be freed below */
		new_page = old_page;
	}
3475
	spin_unlock(ptl);
3476
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
3477
out_release_all:
3478
	put_page(new_page);
3479
out_release_old:
3480
	put_page(old_page);
3481

3482 3483
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
3484 3485
}

3486
/* Return the pagecache page at a given address within a VMA */
3487 3488
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
3489 3490
{
	struct address_space *mapping;
3491
	pgoff_t idx;
3492 3493

	mapping = vma->vm_file->f_mapping;
3494
	idx = vma_hugecache_offset(h, vma, address);
3495 3496 3497 3498

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
3499 3500 3501 3502 3503
/*
 * 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
3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518
			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;
}

3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535
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;
}

3536
static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
3537 3538
			   struct address_space *mapping, pgoff_t idx,
			   unsigned long address, pte_t *ptep, unsigned int flags)
3539
{
3540
	struct hstate *h = hstate_vma(vma);
3541
	int ret = VM_FAULT_SIGBUS;
3542
	int anon_rmap = 0;
A
Adam Litke 已提交
3543 3544
	unsigned long size;
	struct page *page;
3545
	pte_t new_pte;
3546
	spinlock_t *ptl;
A
Adam Litke 已提交
3547

3548 3549 3550
	/*
	 * 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
3551
	 * COW. Warn that such a situation has occurred as it may not be obvious
3552 3553
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3554
		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3555
			   current->pid);
3556 3557 3558
		return ret;
	}

A
Adam Litke 已提交
3559 3560 3561 3562
	/*
	 * Use page lock to guard against racing truncation
	 * before we get page_table_lock.
	 */
3563 3564 3565
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
3566
		size = i_size_read(mapping->host) >> huge_page_shift(h);
3567 3568
		if (idx >= size)
			goto out;
3569
		page = alloc_huge_page(vma, address, 0);
3570
		if (IS_ERR(page)) {
3571 3572 3573 3574 3575
			ret = PTR_ERR(page);
			if (ret == -ENOMEM)
				ret = VM_FAULT_OOM;
			else
				ret = VM_FAULT_SIGBUS;
3576 3577
			goto out;
		}
A
Andrea Arcangeli 已提交
3578
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
3579
		__SetPageUptodate(page);
3580
		set_page_huge_active(page);
3581

3582
		if (vma->vm_flags & VM_MAYSHARE) {
3583
			int err = huge_add_to_page_cache(page, mapping, idx);
3584 3585 3586 3587 3588 3589
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
3590
		} else {
3591
			lock_page(page);
3592 3593 3594 3595
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
3596
			anon_rmap = 1;
3597
		}
3598
	} else {
3599 3600 3601 3602 3603 3604
		/*
		 * 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))) {
3605
			ret = VM_FAULT_HWPOISON |
3606
				VM_FAULT_SET_HINDEX(hstate_index(h));
3607 3608
			goto backout_unlocked;
		}
3609
	}
3610

3611 3612 3613 3614 3615 3616
	/*
	 * 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.
	 */
3617
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3618 3619 3620 3621
		if (vma_needs_reservation(h, vma, address) < 0) {
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
3622
		/* Just decrements count, does not deallocate */
3623
		vma_end_reservation(h, vma, address);
3624
	}
3625

3626 3627
	ptl = huge_pte_lockptr(h, mm, ptep);
	spin_lock(ptl);
3628
	size = i_size_read(mapping->host) >> huge_page_shift(h);
A
Adam Litke 已提交
3629 3630 3631
	if (idx >= size)
		goto backout;

N
Nick Piggin 已提交
3632
	ret = 0;
3633
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
3634 3635
		goto backout;

3636 3637
	if (anon_rmap) {
		ClearPagePrivate(page);
3638
		hugepage_add_new_anon_rmap(page, vma, address);
3639
	} else
3640
		page_dup_rmap(page, true);
3641 3642 3643 3644
	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
				&& (vma->vm_flags & VM_SHARED)));
	set_huge_pte_at(mm, address, ptep, new_pte);

3645
	hugetlb_count_add(pages_per_huge_page(h), mm);
3646
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3647
		/* Optimization, do the COW without a second fault */
3648
		ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
3649 3650
	}

3651
	spin_unlock(ptl);
A
Adam Litke 已提交
3652 3653
	unlock_page(page);
out:
3654
	return ret;
A
Adam Litke 已提交
3655 3656

backout:
3657
	spin_unlock(ptl);
3658
backout_unlocked:
A
Adam Litke 已提交
3659 3660 3661
	unlock_page(page);
	put_page(page);
	goto out;
3662 3663
}

3664
#ifdef CONFIG_SMP
3665
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689
			    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.
 */
3690
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3691 3692 3693 3694 3695 3696 3697 3698
			    struct vm_area_struct *vma,
			    struct address_space *mapping,
			    pgoff_t idx, unsigned long address)
{
	return 0;
}
#endif

3699
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3700
			unsigned long address, unsigned int flags)
3701
{
3702
	pte_t *ptep, entry;
3703
	spinlock_t *ptl;
3704
	int ret;
3705 3706
	u32 hash;
	pgoff_t idx;
3707
	struct page *page = NULL;
3708
	struct page *pagecache_page = NULL;
3709
	struct hstate *h = hstate_vma(vma);
3710
	struct address_space *mapping;
3711
	int need_wait_lock = 0;
3712

3713 3714
	address &= huge_page_mask(h);

3715 3716 3717
	ptep = huge_pte_offset(mm, address);
	if (ptep) {
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
3718
		if (unlikely(is_hugetlb_entry_migration(entry))) {
3719
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
3720 3721
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3722
			return VM_FAULT_HWPOISON_LARGE |
3723
				VM_FAULT_SET_HINDEX(hstate_index(h));
3724 3725 3726 3727
	} else {
		ptep = huge_pte_alloc(mm, address, huge_page_size(h));
		if (!ptep)
			return VM_FAULT_OOM;
3728 3729
	}

3730 3731 3732
	mapping = vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, vma, address);

3733 3734 3735 3736 3737
	/*
	 * 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.
	 */
3738 3739
	hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, address);
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
3740

3741 3742
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
3743
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
3744
		goto out_mutex;
3745
	}
3746

N
Nick Piggin 已提交
3747
	ret = 0;
3748

3749 3750 3751 3752 3753 3754 3755 3756 3757 3758
	/*
	 * 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;

3759 3760 3761 3762 3763 3764 3765 3766
	/*
	 * 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.
	 */
3767
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
3768 3769
		if (vma_needs_reservation(h, vma, address) < 0) {
			ret = VM_FAULT_OOM;
3770
			goto out_mutex;
3771
		}
3772
		/* Just decrements count, does not deallocate */
3773
		vma_end_reservation(h, vma, address);
3774

3775
		if (!(vma->vm_flags & VM_MAYSHARE))
3776 3777 3778 3779
			pagecache_page = hugetlbfs_pagecache_page(h,
								vma, address);
	}

3780 3781 3782 3783 3784 3785
	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;

3786 3787 3788 3789 3790 3791 3792
	/*
	 * 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)
3793 3794 3795 3796
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
3797

3798
	get_page(page);
3799

3800
	if (flags & FAULT_FLAG_WRITE) {
3801
		if (!huge_pte_write(entry)) {
3802
			ret = hugetlb_cow(mm, vma, address, ptep, entry,
3803
					pagecache_page, ptl);
3804
			goto out_put_page;
3805
		}
3806
		entry = huge_pte_mkdirty(entry);
3807 3808
	}
	entry = pte_mkyoung(entry);
3809 3810
	if (huge_ptep_set_access_flags(vma, address, ptep, entry,
						flags & FAULT_FLAG_WRITE))
3811
		update_mmu_cache(vma, address, ptep);
3812 3813 3814 3815
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
3816 3817
out_ptl:
	spin_unlock(ptl);
3818 3819 3820 3821 3822

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
3823
out_mutex:
3824
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
3825 3826 3827 3828 3829 3830 3831 3832 3833
	/*
	 * 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);
3834
	return ret;
3835 3836
}

3837 3838 3839 3840
long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
			 struct page **pages, struct vm_area_struct **vmas,
			 unsigned long *position, unsigned long *nr_pages,
			 long i, unsigned int flags)
D
David Gibson 已提交
3841
{
3842 3843
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
3844
	unsigned long remainder = *nr_pages;
3845
	struct hstate *h = hstate_vma(vma);
D
David Gibson 已提交
3846 3847

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
3848
		pte_t *pte;
3849
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
3850
		int absent;
A
Adam Litke 已提交
3851
		struct page *page;
D
David Gibson 已提交
3852

3853 3854 3855 3856 3857 3858 3859 3860 3861
		/*
		 * 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
3862 3863
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
3864
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
3865
		 * first, for the page indexing below to work.
3866 3867
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
3868
		 */
3869
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
3870 3871
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
3872 3873 3874 3875
		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
3876 3877 3878 3879
		 * 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
3880
		 */
H
Hugh Dickins 已提交
3881 3882
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
3883 3884
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
3885 3886 3887
			remainder = 0;
			break;
		}
D
David Gibson 已提交
3888

3889 3890 3891 3892 3893 3894 3895 3896 3897 3898 3899
		/*
		 * 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)) ||
3900 3901
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
A
Adam Litke 已提交
3902
			int ret;
D
David Gibson 已提交
3903

3904 3905
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
3906 3907
			ret = hugetlb_fault(mm, vma, vaddr,
				(flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
3908
			if (!(ret & VM_FAULT_ERROR))
A
Adam Litke 已提交
3909
				continue;
D
David Gibson 已提交
3910

A
Adam Litke 已提交
3911 3912 3913 3914
			remainder = 0;
			break;
		}

3915
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
3916
		page = pte_page(huge_ptep_get(pte));
3917
same_page:
3918
		if (pages) {
H
Hugh Dickins 已提交
3919
			pages[i] = mem_map_offset(page, pfn_offset);
3920
			get_page(pages[i]);
3921
		}
D
David Gibson 已提交
3922 3923 3924 3925 3926

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
3927
		++pfn_offset;
D
David Gibson 已提交
3928 3929
		--remainder;
		++i;
3930
		if (vaddr < vma->vm_end && remainder &&
3931
				pfn_offset < pages_per_huge_page(h)) {
3932 3933 3934 3935 3936 3937
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
3938
		spin_unlock(ptl);
D
David Gibson 已提交
3939
	}
3940
	*nr_pages = remainder;
D
David Gibson 已提交
3941 3942
	*position = vaddr;

H
Hugh Dickins 已提交
3943
	return i ? i : -EFAULT;
D
David Gibson 已提交
3944
}
3945

3946 3947 3948 3949 3950 3951 3952 3953
#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

3954
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
3955 3956 3957 3958 3959 3960
		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;
3961
	struct hstate *h = hstate_vma(vma);
3962
	unsigned long pages = 0;
3963 3964 3965 3966

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

3967
	mmu_notifier_invalidate_range_start(mm, start, end);
3968
	i_mmap_lock_write(vma->vm_file->f_mapping);
3969
	for (; address < end; address += huge_page_size(h)) {
3970
		spinlock_t *ptl;
3971 3972 3973
		ptep = huge_pte_offset(mm, address);
		if (!ptep)
			continue;
3974
		ptl = huge_pte_lock(h, mm, ptep);
3975 3976
		if (huge_pmd_unshare(mm, &address, ptep)) {
			pages++;
3977
			spin_unlock(ptl);
3978
			continue;
3979
		}
3980 3981 3982 3983 3984 3985 3986 3987 3988 3989 3990 3991 3992 3993 3994 3995 3996 3997 3998 3999
		pte = huge_ptep_get(ptep);
		if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
			spin_unlock(ptl);
			continue;
		}
		if (unlikely(is_hugetlb_entry_migration(pte))) {
			swp_entry_t entry = pte_to_swp_entry(pte);

			if (is_write_migration_entry(entry)) {
				pte_t newpte;

				make_migration_entry_read(&entry);
				newpte = swp_entry_to_pte(entry);
				set_huge_pte_at(mm, address, ptep, newpte);
				pages++;
			}
			spin_unlock(ptl);
			continue;
		}
		if (!huge_pte_none(pte)) {
4000
			pte = huge_ptep_get_and_clear(mm, address, ptep);
4001
			pte = pte_mkhuge(huge_pte_modify(pte, newprot));
4002
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
4003
			set_huge_pte_at(mm, address, ptep, pte);
4004
			pages++;
4005
		}
4006
		spin_unlock(ptl);
4007
	}
4008
	/*
4009
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4010
	 * may have cleared our pud entry and done put_page on the page table:
4011
	 * once we release i_mmap_rwsem, another task can do the final put_page
4012 4013
	 * and that page table be reused and filled with junk.
	 */
4014
	flush_hugetlb_tlb_range(vma, start, end);
4015
	mmu_notifier_invalidate_range(mm, start, end);
4016
	i_mmap_unlock_write(vma->vm_file->f_mapping);
4017
	mmu_notifier_invalidate_range_end(mm, start, end);
4018 4019

	return pages << h->order;
4020 4021
}

4022 4023
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
4024
					struct vm_area_struct *vma,
4025
					vm_flags_t vm_flags)
4026
{
4027
	long ret, chg;
4028
	struct hstate *h = hstate_inode(inode);
4029
	struct hugepage_subpool *spool = subpool_inode(inode);
4030
	struct resv_map *resv_map;
4031
	long gbl_reserve;
4032

4033 4034 4035
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
4036
	 * without using reserves
4037
	 */
4038
	if (vm_flags & VM_NORESERVE)
4039 4040
		return 0;

4041 4042 4043 4044 4045 4046
	/*
	 * 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
	 */
4047
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
4048
		resv_map = inode_resv_map(inode);
4049

4050
		chg = region_chg(resv_map, from, to);
4051 4052 4053

	} else {
		resv_map = resv_map_alloc();
4054 4055 4056
		if (!resv_map)
			return -ENOMEM;

4057
		chg = to - from;
4058

4059 4060 4061 4062
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

4063 4064 4065 4066
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
4067

4068 4069 4070 4071 4072 4073 4074
	/*
	 * 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) {
4075 4076 4077
		ret = -ENOSPC;
		goto out_err;
	}
4078 4079

	/*
4080
	 * Check enough hugepages are available for the reservation.
4081
	 * Hand the pages back to the subpool if there are not
4082
	 */
4083
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
4084
	if (ret < 0) {
4085 4086
		/* put back original number of pages, chg */
		(void)hugepage_subpool_put_pages(spool, chg);
4087
		goto out_err;
K
Ken Chen 已提交
4088
	}
4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100

	/*
	 * 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
	 */
4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118
	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);
		}
	}
4119
	return 0;
4120
out_err:
4121 4122
	if (!vma || vma->vm_flags & VM_MAYSHARE)
		region_abort(resv_map, from, to);
J
Joonsoo Kim 已提交
4123 4124
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
4125
	return ret;
4126 4127
}

4128 4129
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
4130
{
4131
	struct hstate *h = hstate_inode(inode);
4132
	struct resv_map *resv_map = inode_resv_map(inode);
4133
	long chg = 0;
4134
	struct hugepage_subpool *spool = subpool_inode(inode);
4135
	long gbl_reserve;
K
Ken Chen 已提交
4136

4137 4138 4139 4140 4141 4142 4143 4144 4145 4146 4147
	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
4148
	spin_lock(&inode->i_lock);
4149
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
4150 4151
	spin_unlock(&inode->i_lock);

4152 4153 4154 4155 4156 4157
	/*
	 * 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);
4158 4159

	return 0;
4160
}
4161

4162 4163 4164 4165 4166 4167 4168 4169 4170 4171 4172
#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
4173 4174
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4175 4176 4177 4178 4179 4180 4181 4182 4183 4184 4185 4186 4187

	/*
	 * 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;
}

4188
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4189 4190 4191 4192 4193 4194 4195 4196 4197
{
	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)
4198 4199
		return true;
	return false;
4200 4201 4202 4203 4204 4205 4206
}

/*
 * 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
4207
 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220
 * 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;
4221
	spinlock_t *ptl;
4222 4223 4224 4225

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

4226
	i_mmap_lock_write(mapping);
4227 4228 4229 4230 4231 4232 4233 4234 4235 4236 4237 4238 4239 4240 4241 4242 4243
	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

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

	if (!spte)
		goto out;

4244 4245
	ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
	spin_lock(ptl);
4246
	if (pud_none(*pud)) {
4247 4248
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
4249
		mm_inc_nr_pmds(mm);
4250
	} else {
4251
		put_page(virt_to_page(spte));
4252
	}
4253
	spin_unlock(ptl);
4254 4255
out:
	pte = (pte_t *)pmd_alloc(mm, pud, addr);
4256
	i_mmap_unlock_write(mapping);
4257 4258 4259 4260 4261 4262 4263 4264 4265 4266
	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.
 *
4267
 * called with page table lock held.
4268 4269 4270 4271 4272 4273 4274 4275 4276 4277 4278 4279 4280 4281 4282
 *
 * returns: 1 successfully unmapped a shared pte page
 *	    0 the underlying pte page is not shared, or it is the last user
 */
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	pgd_t *pgd = pgd_offset(mm, *addr);
	pud_t *pud = pud_offset(pgd, *addr);

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

	pud_clear(pud);
	put_page(virt_to_page(ptep));
4283
	mm_dec_nr_pmds(mm);
4284 4285 4286
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
4287 4288 4289 4290 4291 4292
#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;
}
4293 4294 4295 4296 4297

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	return 0;
}
4298
#define want_pmd_share()	(0)
4299 4300
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
	pud = pud_alloc(mm, pgd, addr);
	if (pud) {
		if (sz == PUD_SIZE) {
			pte = (pte_t *)pud;
		} else {
			BUG_ON(sz != PMD_SIZE);
			if (want_pmd_share() && pud_none(*pud))
				pte = huge_pmd_share(mm, addr, pud);
			else
				pte = (pte_t *)pmd_alloc(mm, pud, addr);
		}
	}
4322
	BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
4323 4324 4325 4326 4327 4328 4329 4330 4331 4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344

	return pte;
}

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

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

4345 4346 4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357 4358
#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */

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

struct page * __weak
4359
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4360
		pmd_t *pmd, int flags)
4361
{
4362 4363 4364 4365 4366 4367 4368 4369 4370 4371 4372 4373
	struct page *page = NULL;
	spinlock_t *ptl;
retry:
	ptl = pmd_lockptr(mm, pmd);
	spin_lock(ptl);
	/*
	 * make sure that the address range covered by this pmd is not
	 * unmapped from other threads.
	 */
	if (!pmd_huge(*pmd))
		goto out;
	if (pmd_present(*pmd)) {
4374
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388 4389
		if (flags & FOLL_GET)
			get_page(page);
	} else {
		if (is_hugetlb_entry_migration(huge_ptep_get((pte_t *)pmd))) {
			spin_unlock(ptl);
			__migration_entry_wait(mm, (pte_t *)pmd, ptl);
			goto retry;
		}
		/*
		 * hwpoisoned entry is treated as no_page_table in
		 * follow_page_mask().
		 */
	}
out:
	spin_unlock(ptl);
4390 4391 4392
	return page;
}

4393
struct page * __weak
4394
follow_huge_pud(struct mm_struct *mm, unsigned long address,
4395
		pud_t *pud, int flags)
4396
{
4397 4398
	if (flags & FOLL_GET)
		return NULL;
4399

4400
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4401 4402
}

4403 4404
#ifdef CONFIG_MEMORY_FAILURE

4405 4406 4407
/*
 * This function is called from memory failure code.
 */
4408
int dequeue_hwpoisoned_huge_page(struct page *hpage)
4409 4410 4411
{
	struct hstate *h = page_hstate(hpage);
	int nid = page_to_nid(hpage);
4412
	int ret = -EBUSY;
4413 4414

	spin_lock(&hugetlb_lock);
4415 4416 4417 4418 4419
	/*
	 * Just checking !page_huge_active is not enough, because that could be
	 * an isolated/hwpoisoned hugepage (which have >0 refcount).
	 */
	if (!page_huge_active(hpage) && !page_count(hpage)) {
4420 4421 4422 4423 4424 4425 4426
		/*
		 * Hwpoisoned hugepage isn't linked to activelist or freelist,
		 * but dangling hpage->lru can trigger list-debug warnings
		 * (this happens when we call unpoison_memory() on it),
		 * so let it point to itself with list_del_init().
		 */
		list_del_init(&hpage->lru);
4427
		set_page_refcounted(hpage);
4428 4429 4430 4431
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
		ret = 0;
	}
4432
	spin_unlock(&hugetlb_lock);
4433
	return ret;
4434
}
4435
#endif
4436 4437 4438

bool isolate_huge_page(struct page *page, struct list_head *list)
{
4439 4440
	bool ret = true;

4441
	VM_BUG_ON_PAGE(!PageHead(page), page);
4442
	spin_lock(&hugetlb_lock);
4443 4444 4445 4446 4447
	if (!page_huge_active(page) || !get_page_unless_zero(page)) {
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
4448
	list_move_tail(&page->lru, list);
4449
unlock:
4450
	spin_unlock(&hugetlb_lock);
4451
	return ret;
4452 4453 4454 4455
}

void putback_active_hugepage(struct page *page)
{
4456
	VM_BUG_ON_PAGE(!PageHead(page), page);
4457
	spin_lock(&hugetlb_lock);
4458
	set_page_huge_active(page);
4459 4460 4461 4462
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}