hugetlb.c 134.6 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/memblock.h>
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#include <linux/sysfs.h>
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#include <linux/slab.h>
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#include <linux/mmdebug.h>
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#include <linux/sched/signal.h>
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#include <linux/rmap.h>
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#include <linux/string_helpers.h>
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#include <linux/swap.h>
#include <linux/swapops.h>
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#include <linux/jhash.h>
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#include <linux/numa.h>
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#include <asm/page.h>
#include <asm/pgtable.h>
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#include <asm/tlb.h>
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#include <linux/io.h>
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#include <linux/hugetlb.h>
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#include <linux/hugetlb_cgroup.h>
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#include <linux/node.h>
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#include <linux/userfaultfd_k.h>
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#include <linux/page_owner.h>
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#include "internal.h"
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int hugetlb_max_hstate __read_mostly;
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unsigned int default_hstate_idx;
struct hstate hstates[HUGE_MAX_HSTATE];
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/*
 * Minimum page order among possible hugepage sizes, set to a proper value
 * at boot time.
 */
static unsigned int minimum_order __read_mostly = UINT_MAX;
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__initdata LIST_HEAD(huge_boot_pages);

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/* for command line parsing */
static struct hstate * __initdata parsed_hstate;
static unsigned long __initdata default_hstate_max_huge_pages;
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static unsigned long __initdata default_hstate_size;
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static bool __initdata parsed_valid_hugepagesz = true;
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59
/*
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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;

182
	if (!spool)
183
		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)
261
{
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	struct list_head *head = &resv->regions;
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	struct file_region *rg, *nrg, *trg;
264
	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)
357
{
358
	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;
383
		}
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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) {
400
		if (!nrg) {
401
			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.
482
 */
483
static long region_del(struct resv_map *resv, long f, long t)
484
{
485
	struct list_head *head = &resv->regions;
486
	struct file_region *rg, *trg;
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	struct file_region *nrg = NULL;
	long del = 0;
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490
retry:
491
	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))
501
			continue;
502

503
		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;
540
			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;
		}
557
	}
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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.
 */
573
void hugetlb_fix_reserve_counts(struct inode *inode)
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{
	struct hugepage_subpool *spool = subpool_inode(inode);
	long rsv_adjust;

	rsv_adjust = hugepage_subpool_get_pages(spool, 1);
579
	if (rsv_adjust) {
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		struct hstate *h = hstate_inode(inode);

		hugetlb_acct_memory(h, 1);
	}
}

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/*
 * Count and return the number of huge pages in the reserve map
 * that intersect with the range [f, t).
 */
590
static long region_count(struct resv_map *resv, long f, long t)
591
{
592
	struct list_head *head = &resv->regions;
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	struct file_region *rg;
	long chg = 0;

596
	spin_lock(&resv->lock);
597 598
	/* 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.
 */
621 622
static pgoff_t vma_hugecache_offset(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
623
{
624 625
	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);
}
633
EXPORT_SYMBOL_GPL(linear_hugepage_index);
634

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/*
 * Return the size of the pages allocated when backing a VMA. In the majority
 * cases this will be same size as used by the page table entries.
 */
unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
{
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	if (vma->vm_ops && vma->vm_ops->pagesize)
		return vma->vm_ops->pagesize(vma);
	return PAGE_SIZE;
644
}
645
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
646

647 648 649
/*
 * 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
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 * architectures where it differs, an architecture-specific 'strong'
 * version of this symbol is required.
652
 */
653
__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
654 655 656 657
{
	return vma_kernel_pagesize(vma);
}

658 659 660 661 662 663 664
/*
 * Flags for MAP_PRIVATE reservations.  These are stored in the bottom
 * bits of the reservation map pointer, which are always clear due to
 * alignment.
 */
#define HPAGE_RESV_OWNER    (1UL << 0)
#define HPAGE_RESV_UNMAPPED (1UL << 1)
665
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
666

667 668 669 670 671 672 673 674 675
/*
 * These helpers are used to track how many pages are reserved for
 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
 * is guaranteed to have their future faults succeed.
 *
 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
 * the reserve counters are updated with the hugetlb_lock held. It is safe
 * to reset the VMA at fork() time as it is not in use yet and there is no
 * chance of the global counters getting corrupted as a result of the values.
676 677 678 679 680 681 682 683 684
 *
 * The private mapping reservation is represented in a subtly different
 * manner to a shared mapping.  A shared mapping has a region map associated
 * with the underlying file, this region map represents the backing file
 * pages which have ever had a reservation assigned which this persists even
 * after the page is instantiated.  A private mapping has a region map
 * associated with the original mmap which is attached to all VMAs which
 * reference it, this region map represents those offsets which have consumed
 * reservation ie. where pages have been instantiated.
685
 */
686 687 688 689 690 691 692 693 694 695 696
static unsigned long get_vma_private_data(struct vm_area_struct *vma)
{
	return (unsigned long)vma->vm_private_data;
}

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

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

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

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

712 713 714 715 716 717
	resv_map->adds_in_progress = 0;

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

718 719 720
	return resv_map;
}

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

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

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

	VM_BUG_ON(resv_map->adds_in_progress);

738 739 740
	kfree(resv_map);
}

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

746
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
747
{
748
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
749 750 751 752 753 754 755
	if (vma->vm_flags & VM_MAYSHARE) {
		struct address_space *mapping = vma->vm_file->f_mapping;
		struct inode *inode = mapping->host;

		return inode_resv_map(inode);

	} else {
756 757
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
758
	}
759 760
}

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

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

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

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

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

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

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

/* Returns true if the VMA has associated reserve pages */
794
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
795
{
796 797 798 799 800 801 802 803 804 805 806
	if (vma->vm_flags & VM_NORESERVE) {
		/*
		 * This address is already reserved by other process(chg == 0),
		 * so, we should decrement reserved count. Without decrementing,
		 * reserve count remains after releasing inode, because this
		 * allocated page will go into page cache and is regarded as
		 * coming from reserved pool in releasing step.  Currently, we
		 * don't have any other solution to deal with this situation
		 * properly, so add work-around here.
		 */
		if (vma->vm_flags & VM_MAYSHARE && chg == 0)
807
			return true;
808
		else
809
			return false;
810
	}
811 812

	/* Shared mappings always use reserves */
813 814 815 816 817 818 819 820 821 822 823 824 825
	if (vma->vm_flags & VM_MAYSHARE) {
		/*
		 * We know VM_NORESERVE is not set.  Therefore, there SHOULD
		 * be a region map for all pages.  The only situation where
		 * there is no region map is if a hole was punched via
		 * fallocate.  In this case, there really are no reverves to
		 * use.  This situation is indicated if chg != 0.
		 */
		if (chg)
			return false;
		else
			return true;
	}
826 827 828 829 830

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851
	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;
	}
852

853
	return false;
854 855
}

856
static void enqueue_huge_page(struct hstate *h, struct page *page)
L
Linus Torvalds 已提交
857 858
{
	int nid = page_to_nid(page);
859
	list_move(&page->lru, &h->hugepage_freelists[nid]);
860 861
	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
L
Linus Torvalds 已提交
862 863
}

864
static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
865 866 867
{
	struct page *page;

868
	list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
869
		if (!PageHWPoison(page))
870 871 872 873 874 875
			break;
	/*
	 * if 'non-isolated free hugepage' not found on the list,
	 * the allocation fails.
	 */
	if (&h->hugepage_freelists[nid] == &page->lru)
876
		return NULL;
877
	list_move(&page->lru, &h->hugepage_activelist);
878
	set_page_refcounted(page);
879 880 881 882 883
	h->free_huge_pages--;
	h->free_huge_pages_node[nid]--;
	return page;
}

884 885
static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
		nodemask_t *nmask)
886
{
887 888 889 890
	unsigned int cpuset_mems_cookie;
	struct zonelist *zonelist;
	struct zone *zone;
	struct zoneref *z;
891
	int node = NUMA_NO_NODE;
892

893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908
	zonelist = node_zonelist(nid, gfp_mask);

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

		if (!cpuset_zone_allowed(zone, gfp_mask))
			continue;
		/*
		 * no need to ask again on the same node. Pool is node rather than
		 * zone aware
		 */
		if (zone_to_nid(zone) == node)
			continue;
		node = zone_to_nid(zone);
909 910 911 912 913

		page = dequeue_huge_page_node_exact(h, node);
		if (page)
			return page;
	}
914 915 916
	if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
		goto retry_cpuset;

917 918 919
	return NULL;
}

920 921 922
/* Movability of hugepages depends on migration support. */
static inline gfp_t htlb_alloc_mask(struct hstate *h)
{
923
	if (hugepage_movable_supported(h))
924 925 926 927 928
		return GFP_HIGHUSER_MOVABLE;
	else
		return GFP_HIGHUSER;
}

929 930
static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
931 932
				unsigned long address, int avoid_reserve,
				long chg)
L
Linus Torvalds 已提交
933
{
934
	struct page *page;
935
	struct mempolicy *mpol;
936
	gfp_t gfp_mask;
937
	nodemask_t *nodemask;
938
	int nid;
L
Linus Torvalds 已提交
939

940 941 942 943 944
	/*
	 * 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
	 */
945
	if (!vma_has_reserves(vma, chg) &&
946
			h->free_huge_pages - h->resv_huge_pages == 0)
947
		goto err;
948

949
	/* If reserves cannot be used, ensure enough pages are in the pool */
950
	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
951
		goto err;
952

953 954
	gfp_mask = htlb_alloc_mask(h);
	nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
955 956 957 958
	page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
	if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
		SetPagePrivate(page);
		h->resv_huge_pages--;
L
Linus Torvalds 已提交
959
	}
960

961
	mpol_cond_put(mpol);
L
Linus Torvalds 已提交
962
	return page;
963 964 965

err:
	return NULL;
L
Linus Torvalds 已提交
966 967
}

968 969 970 971 972 973 974 975 976
/*
 * 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)
{
977
	nid = next_node_in(nid, *nodes_allowed);
978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038
	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--)

1039
#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1040
static void destroy_compound_gigantic_page(struct page *page,
1041
					unsigned int order)
1042 1043 1044 1045 1046
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

1047
	atomic_set(compound_mapcount_ptr(page), 0);
1048
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1049
		clear_compound_head(p);
1050 1051 1052 1053 1054 1055 1056
		set_page_refcounted(p);
	}

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

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

1062
#ifdef CONFIG_CONTIG_ALLOC
1063
static int __alloc_gigantic_page(unsigned long start_pfn,
1064
				unsigned long nr_pages, gfp_t gfp_mask)
1065 1066
{
	unsigned long end_pfn = start_pfn + nr_pages;
1067
	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
1068
				  gfp_mask);
1069 1070
}

1071 1072
static bool pfn_range_valid_gigantic(struct zone *z,
			unsigned long start_pfn, unsigned long nr_pages)
1073 1074 1075 1076 1077 1078 1079 1080 1081 1082
{
	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);

1083 1084 1085
		if (page_zone(page) != z)
			return false;

1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105
		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);
}

1106 1107
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
		int nid, nodemask_t *nodemask)
1108
{
1109
	unsigned int order = huge_page_order(h);
1110 1111
	unsigned long nr_pages = 1 << order;
	unsigned long ret, pfn, flags;
1112 1113 1114
	struct zonelist *zonelist;
	struct zone *zone;
	struct zoneref *z;
1115

1116
	zonelist = node_zonelist(nid, gfp_mask);
1117
	for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nodemask) {
1118
		spin_lock_irqsave(&zone->lock, flags);
1119

1120 1121 1122
		pfn = ALIGN(zone->zone_start_pfn, nr_pages);
		while (zone_spans_last_pfn(zone, pfn, nr_pages)) {
			if (pfn_range_valid_gigantic(zone, pfn, nr_pages)) {
1123 1124 1125 1126 1127 1128 1129
				/*
				 * 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...
				 */
1130 1131
				spin_unlock_irqrestore(&zone->lock, flags);
				ret = __alloc_gigantic_page(pfn, nr_pages, gfp_mask);
1132 1133
				if (!ret)
					return pfn_to_page(pfn);
1134
				spin_lock_irqsave(&zone->lock, flags);
1135 1136 1137 1138
			}
			pfn += nr_pages;
		}

1139
		spin_unlock_irqrestore(&zone->lock, flags);
1140 1141 1142 1143 1144 1145
	}

	return NULL;
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1146
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1147 1148 1149 1150 1151 1152 1153
#else /* !CONFIG_CONTIG_ALLOC */
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
					int nid, nodemask_t *nodemask)
{
	return NULL;
}
#endif /* CONFIG_CONTIG_ALLOC */
1154

1155
#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1156
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1157 1158 1159 1160
					int nid, nodemask_t *nodemask)
{
	return NULL;
}
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
#endif

1166
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1167 1168
{
	int i;
1169

1170
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1171
		return;
1172

1173 1174 1175
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
1176 1177
		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
1178 1179
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1180
	}
1181
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1182
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1183
	set_page_refcounted(page);
1184 1185 1186 1187 1188 1189
	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
1190 1191
}

1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202
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;
}

1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
/*
 * 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]);
}

1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249
/*
 * Internal hugetlb specific page flag. Do not use outside of the hugetlb
 * code
 */
static inline bool PageHugeTemporary(struct page *page)
{
	if (!PageHuge(page))
		return false;

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

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

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

1250
void free_huge_page(struct page *page)
1251
{
1252 1253 1254 1255
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1256
	struct hstate *h = page_hstate(page);
1257
	int nid = page_to_nid(page);
1258 1259
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1260
	bool restore_reserve;
1261

1262 1263
	VM_BUG_ON_PAGE(page_count(page), page);
	VM_BUG_ON_PAGE(page_mapcount(page), page);
1264 1265 1266

	set_page_private(page, 0);
	page->mapping = NULL;
1267
	restore_reserve = PagePrivate(page);
1268
	ClearPagePrivate(page);
1269

1270
	/*
1271 1272 1273 1274 1275 1276
	 * If PagePrivate() was set on page, page allocation consumed a
	 * reservation.  If the page was associated with a subpool, there
	 * would have been a page reserved in the subpool before allocation
	 * via hugepage_subpool_get_pages().  Since we are 'restoring' the
	 * reservtion, do not call hugepage_subpool_put_pages() as this will
	 * remove the reserved page from the subpool.
1277
	 */
1278 1279 1280 1281 1282 1283 1284 1285 1286 1287
	if (!restore_reserve) {
		/*
		 * 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;
	}
1288

1289
	spin_lock(&hugetlb_lock);
1290
	clear_page_huge_active(page);
1291 1292
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1293 1294 1295
	if (restore_reserve)
		h->resv_huge_pages++;

1296 1297 1298 1299 1300
	if (PageHugeTemporary(page)) {
		list_del(&page->lru);
		ClearPageHugeTemporary(page);
		update_and_free_page(h, page);
	} else if (h->surplus_huge_pages_node[nid]) {
1301 1302
		/* remove the page from active list */
		list_del(&page->lru);
1303 1304 1305
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1306
	} else {
1307
		arch_clear_hugepage_flags(page);
1308
		enqueue_huge_page(h, page);
1309
	}
1310 1311 1312
	spin_unlock(&hugetlb_lock);
}

1313
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1314
{
1315
	INIT_LIST_HEAD(&page->lru);
1316
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1317
	spin_lock(&hugetlb_lock);
1318
	set_hugetlb_cgroup(page, NULL);
1319 1320
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1321 1322 1323
	spin_unlock(&hugetlb_lock);
}

1324
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1325 1326 1327 1328 1329 1330 1331
{
	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);
1332
	__ClearPageReserved(page);
1333
	__SetPageHead(page);
1334
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347
		/*
		 * 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);
1348
		set_page_count(p, 0);
1349
		set_compound_head(p, page);
1350
	}
1351
	atomic_set(compound_mapcount_ptr(page), -1);
1352 1353
}

A
Andrew Morton 已提交
1354 1355 1356 1357 1358
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1359 1360 1361 1362 1363 1364
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1365
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1366
}
1367 1368
EXPORT_SYMBOL_GPL(PageHuge);

1369 1370 1371 1372 1373 1374 1375 1376 1377
/*
 * 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;

1378
	return get_compound_page_dtor(page_head) == free_huge_page;
1379 1380
}

1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397
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;
}

1398
static struct page *alloc_buddy_huge_page(struct hstate *h,
1399
		gfp_t gfp_mask, int nid, nodemask_t *nmask)
L
Linus Torvalds 已提交
1400
{
1401
	int order = huge_page_order(h);
L
Linus Torvalds 已提交
1402
	struct page *page;
1403

1404 1405 1406 1407 1408 1409 1410 1411
	gfp_mask |= __GFP_COMP|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;
	if (nid == NUMA_NO_NODE)
		nid = numa_mem_id();
	page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask);
	if (page)
		__count_vm_event(HTLB_BUDDY_PGALLOC);
	else
		__count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
1412 1413 1414 1415

	return page;
}

1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439
/*
 * Common helper to allocate a fresh hugetlb page. All specific allocators
 * should use this function to get new hugetlb pages
 */
static struct page *alloc_fresh_huge_page(struct hstate *h,
		gfp_t gfp_mask, int nid, nodemask_t *nmask)
{
	struct page *page;

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

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

	return page;
}

1440 1441 1442 1443
/*
 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
 * manner.
 */
1444
static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
1445 1446 1447
{
	struct page *page;
	int nr_nodes, node;
1448
	gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1449 1450

	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1451
		page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed);
1452
		if (page)
1453 1454 1455
			break;
	}

1456 1457
	if (!page)
		return 0;
1458

1459 1460 1461
	put_page(page); /* free it into the hugepage allocator */

	return 1;
1462 1463
}

1464 1465 1466 1467 1468 1469
/*
 * 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.
 */
1470 1471
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1472
{
1473
	int nr_nodes, node;
1474 1475
	int ret = 0;

1476
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1477 1478 1479 1480
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1481 1482
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1483
			struct page *page =
1484
				list_entry(h->hugepage_freelists[node].next,
1485 1486 1487
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1488
			h->free_huge_pages_node[node]--;
1489 1490
			if (acct_surplus) {
				h->surplus_huge_pages--;
1491
				h->surplus_huge_pages_node[node]--;
1492
			}
1493 1494
			update_and_free_page(h, page);
			ret = 1;
1495
			break;
1496
		}
1497
	}
1498 1499 1500 1501

	return ret;
}

1502 1503
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
1504
 * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
1505 1506
 * dissolution fails because a give page is not a free hugepage, or because
 * free hugepages are fully reserved.
1507
 */
1508
int dissolve_free_huge_page(struct page *page)
1509
{
1510
	int rc = -EBUSY;
1511

1512 1513
	spin_lock(&hugetlb_lock);
	if (PageHuge(page) && !page_count(page)) {
1514 1515 1516
		struct page *head = compound_head(page);
		struct hstate *h = page_hstate(head);
		int nid = page_to_nid(head);
1517
		if (h->free_huge_pages - h->resv_huge_pages == 0)
1518
			goto out;
1519 1520 1521 1522 1523 1524 1525 1526
		/*
		 * Move PageHWPoison flag from head page to the raw error page,
		 * which makes any subpages rather than the error page reusable.
		 */
		if (PageHWPoison(head) && page != head) {
			SetPageHWPoison(page);
			ClearPageHWPoison(head);
		}
1527
		list_del(&head->lru);
1528 1529
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
1530
		h->max_huge_pages--;
1531
		update_and_free_page(h, head);
1532
		rc = 0;
1533
	}
1534
out:
1535
	spin_unlock(&hugetlb_lock);
1536
	return rc;
1537 1538 1539 1540 1541
}

/*
 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 * make specified memory blocks removable from the system.
1542 1543
 * Note that this will dissolve a free gigantic hugepage completely, if any
 * part of it lies within the given range.
1544 1545
 * Also note that if dissolve_free_huge_page() returns with an error, all
 * free hugepages that were dissolved before that error are lost.
1546
 */
1547
int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1548 1549
{
	unsigned long pfn;
1550
	struct page *page;
1551
	int rc = 0;
1552

1553
	if (!hugepages_supported())
1554
		return rc;
1555

1556 1557 1558 1559 1560 1561 1562 1563
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
		page = pfn_to_page(pfn);
		if (PageHuge(page) && !page_count(page)) {
			rc = dissolve_free_huge_page(page);
			if (rc)
				break;
		}
	}
1564 1565

	return rc;
1566 1567
}

1568 1569 1570
/*
 * Allocates a fresh surplus page from the page allocator.
 */
1571
static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1572
		int nid, nodemask_t *nmask)
1573
{
1574
	struct page *page = NULL;
1575

1576
	if (hstate_is_gigantic(h))
1577 1578
		return NULL;

1579
	spin_lock(&hugetlb_lock);
1580 1581
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
		goto out_unlock;
1582 1583
	spin_unlock(&hugetlb_lock);

1584
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask);
1585
	if (!page)
1586
		return NULL;
1587 1588

	spin_lock(&hugetlb_lock);
1589 1590 1591 1592 1593 1594 1595 1596 1597
	/*
	 * We could have raced with the pool size change.
	 * Double check that and simply deallocate the new page
	 * if we would end up overcommiting the surpluses. Abuse
	 * temporary page to workaround the nasty free_huge_page
	 * codeflow
	 */
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
		SetPageHugeTemporary(page);
1598
		spin_unlock(&hugetlb_lock);
1599
		put_page(page);
1600
		return NULL;
1601 1602
	} else {
		h->surplus_huge_pages++;
1603
		h->surplus_huge_pages_node[page_to_nid(page)]++;
1604
	}
1605 1606

out_unlock:
1607
	spin_unlock(&hugetlb_lock);
1608 1609 1610 1611

	return page;
}

1612 1613
struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
				     int nid, nodemask_t *nmask)
1614 1615 1616 1617 1618 1619
{
	struct page *page;

	if (hstate_is_gigantic(h))
		return NULL;

1620
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask);
1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632
	if (!page)
		return NULL;

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

	return page;
}

1633 1634 1635
/*
 * Use the VMA's mpolicy to allocate a huge page from the buddy.
 */
D
Dave Hansen 已提交
1636
static
1637
struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1638 1639
		struct vm_area_struct *vma, unsigned long addr)
{
1640 1641 1642 1643 1644 1645 1646
	struct page *page;
	struct mempolicy *mpol;
	gfp_t gfp_mask = htlb_alloc_mask(h);
	int nid;
	nodemask_t *nodemask;

	nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
1647
	page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1648 1649 1650
	mpol_cond_put(mpol);

	return page;
1651 1652
}

1653
/* page migration callback function */
1654 1655
struct page *alloc_huge_page_node(struct hstate *h, int nid)
{
1656
	gfp_t gfp_mask = htlb_alloc_mask(h);
1657
	struct page *page = NULL;
1658

1659 1660 1661
	if (nid != NUMA_NO_NODE)
		gfp_mask |= __GFP_THISNODE;

1662
	spin_lock(&hugetlb_lock);
1663
	if (h->free_huge_pages - h->resv_huge_pages > 0)
1664
		page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL);
1665 1666
	spin_unlock(&hugetlb_lock);

1667
	if (!page)
1668
		page = alloc_migrate_huge_page(h, gfp_mask, nid, NULL);
1669 1670 1671 1672

	return page;
}

1673
/* page migration callback function */
1674 1675
struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
		nodemask_t *nmask)
1676
{
1677
	gfp_t gfp_mask = htlb_alloc_mask(h);
1678 1679 1680

	spin_lock(&hugetlb_lock);
	if (h->free_huge_pages - h->resv_huge_pages > 0) {
1681 1682 1683 1684 1685 1686
		struct page *page;

		page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
		if (page) {
			spin_unlock(&hugetlb_lock);
			return page;
1687 1688 1689 1690
		}
	}
	spin_unlock(&hugetlb_lock);

1691
	return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1692 1693
}

1694
/* mempolicy aware migration callback */
1695 1696
struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
		unsigned long address)
1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711
{
	struct mempolicy *mpol;
	nodemask_t *nodemask;
	struct page *page;
	gfp_t gfp_mask;
	int node;

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

	return page;
}

1712
/*
L
Lucas De Marchi 已提交
1713
 * Increase the hugetlb pool such that it can accommodate a reservation
1714 1715
 * of size 'delta'.
 */
1716
static int gather_surplus_pages(struct hstate *h, int delta)
1717 1718 1719 1720 1721
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
1722
	bool alloc_ok = true;
1723

1724
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1725
	if (needed <= 0) {
1726
		h->resv_huge_pages += delta;
1727
		return 0;
1728
	}
1729 1730 1731 1732 1733 1734 1735 1736

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
1737
		page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
1738
				NUMA_NO_NODE, NULL);
1739 1740 1741 1742
		if (!page) {
			alloc_ok = false;
			break;
		}
1743
		list_add(&page->lru, &surplus_list);
1744
		cond_resched();
1745
	}
1746
	allocated += i;
1747 1748 1749 1750 1751 1752

	/*
	 * 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);
1753 1754
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
1755 1756 1757 1758 1759 1760 1761 1762 1763 1764
	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;
	}
1765 1766
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
1767
	 * needed to accommodate the reservation.  Add the appropriate number
1768
	 * of pages to the hugetlb pool and free the extras back to the buddy
1769 1770 1771
	 * 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.
1772 1773
	 */
	needed += allocated;
1774
	h->resv_huge_pages += delta;
1775
	ret = 0;
1776

1777
	/* Free the needed pages to the hugetlb pool */
1778
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
1779 1780
		if ((--needed) < 0)
			break;
1781 1782 1783 1784 1785
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
1786
		VM_BUG_ON_PAGE(page_count(page), page);
1787
		enqueue_huge_page(h, page);
1788
	}
1789
free:
1790
	spin_unlock(&hugetlb_lock);
1791 1792

	/* Free unnecessary surplus pages to the buddy allocator */
1793 1794
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
1795
	spin_lock(&hugetlb_lock);
1796 1797 1798 1799 1800

	return ret;
}

/*
1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812
 * This routine has two main purposes:
 * 1) Decrement the reservation count (resv_huge_pages) by the value passed
 *    in unused_resv_pages.  This corresponds to the prior adjustments made
 *    to the associated reservation map.
 * 2) Free any unused surplus pages that may have been allocated to satisfy
 *    the reservation.  As many as unused_resv_pages may be freed.
 *
 * Called with hugetlb_lock held.  However, the lock could be dropped (and
 * reacquired) during calls to cond_resched_lock.  Whenever dropping the lock,
 * we must make sure nobody else can claim pages we are in the process of
 * freeing.  Do this by ensuring resv_huge_page always is greater than the
 * number of huge pages we plan to free when dropping the lock.
1813
 */
1814 1815
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
1816 1817 1818
{
	unsigned long nr_pages;

1819
	/* Cannot return gigantic pages currently */
1820
	if (hstate_is_gigantic(h))
1821
		goto out;
1822

1823 1824 1825 1826
	/*
	 * Part (or even all) of the reservation could have been backed
	 * by pre-allocated pages. Only free surplus pages.
	 */
1827
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
1828

1829 1830
	/*
	 * We want to release as many surplus pages as possible, spread
1831 1832 1833 1834 1835
	 * 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.
1836 1837 1838 1839
	 *
	 * Note that we decrement resv_huge_pages as we free the pages.  If
	 * we drop the lock, resv_huge_pages will still be sufficiently large
	 * to cover subsequent pages we may free.
1840 1841
	 */
	while (nr_pages--) {
1842 1843
		h->resv_huge_pages--;
		unused_resv_pages--;
1844
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
1845
			goto out;
1846
		cond_resched_lock(&hugetlb_lock);
1847
	}
1848 1849 1850 1851

out:
	/* Fully uncommit the reservation */
	h->resv_huge_pages -= unused_resv_pages;
1852 1853
}

1854

1855
/*
1856
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
1857
 * are used by the huge page allocation routines to manage reservations.
1858 1859 1860 1861 1862 1863
 *
 * 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
1864 1865 1866
 * 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.
1867 1868 1869 1870 1871 1872
 *
 * 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.
1873 1874 1875 1876 1877
 *
 * vma_add_reservation is used in error paths where a reservation must
 * be restored when a newly allocated huge page must be freed.  It is
 * to be called after calling vma_needs_reservation to determine if a
 * reservation exists.
1878
 */
1879 1880 1881
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
1882
	VMA_END_RESV,
1883
	VMA_ADD_RESV,
1884
};
1885 1886
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
1887
				enum vma_resv_mode mode)
1888
{
1889 1890
	struct resv_map *resv;
	pgoff_t idx;
1891
	long ret;
1892

1893 1894
	resv = vma_resv_map(vma);
	if (!resv)
1895
		return 1;
1896

1897
	idx = vma_hugecache_offset(h, vma, addr);
1898 1899
	switch (mode) {
	case VMA_NEEDS_RESV:
1900
		ret = region_chg(resv, idx, idx + 1);
1901 1902 1903 1904
		break;
	case VMA_COMMIT_RESV:
		ret = region_add(resv, idx, idx + 1);
		break;
1905
	case VMA_END_RESV:
1906 1907 1908
		region_abort(resv, idx, idx + 1);
		ret = 0;
		break;
1909 1910 1911 1912 1913 1914 1915 1916
	case VMA_ADD_RESV:
		if (vma->vm_flags & VM_MAYSHARE)
			ret = region_add(resv, idx, idx + 1);
		else {
			region_abort(resv, idx, idx + 1);
			ret = region_del(resv, idx, idx + 1);
		}
		break;
1917 1918 1919
	default:
		BUG();
	}
1920

1921
	if (vma->vm_flags & VM_MAYSHARE)
1922
		return ret;
1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941
	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;
	}
1942
	else
1943
		return ret < 0 ? ret : 0;
1944
}
1945 1946

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

1952 1953 1954
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
1955 1956 1957
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

1958
static void vma_end_reservation(struct hstate *h,
1959 1960
			struct vm_area_struct *vma, unsigned long addr)
{
1961
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
1962 1963
}

1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
static long vma_add_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
	return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
}

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

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

2014
struct page *alloc_huge_page(struct vm_area_struct *vma,
2015
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
2016
{
2017
	struct hugepage_subpool *spool = subpool_vma(vma);
2018
	struct hstate *h = hstate_vma(vma);
2019
	struct page *page;
2020 2021
	long map_chg, map_commit;
	long gbl_chg;
2022 2023
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
2024

2025
	idx = hstate_index(h);
2026
	/*
2027 2028 2029
	 * 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).
2030
	 */
2031 2032
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
2033
		return ERR_PTR(-ENOMEM);
2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044

	/*
	 * 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) {
2045
			vma_end_reservation(h, vma, addr);
2046
			return ERR_PTR(-ENOSPC);
2047
		}
L
Linus Torvalds 已提交
2048

2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060
		/*
		 * 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;
	}

2061
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2062 2063 2064
	if (ret)
		goto out_subpool_put;

L
Linus Torvalds 已提交
2065
	spin_lock(&hugetlb_lock);
2066 2067 2068 2069 2070 2071
	/*
	 * 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);
2072
	if (!page) {
2073
		spin_unlock(&hugetlb_lock);
2074
		page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2075 2076
		if (!page)
			goto out_uncharge_cgroup;
2077 2078 2079 2080
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
2081 2082
		spin_lock(&hugetlb_lock);
		list_move(&page->lru, &h->hugepage_activelist);
2083
		/* Fall through */
K
Ken Chen 已提交
2084
	}
2085 2086
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
	spin_unlock(&hugetlb_lock);
2087

2088
	set_page_private(page, (unsigned long)spool);
2089

2090 2091
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105
		/*
		 * 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);
	}
2106
	return page;
2107 2108 2109 2110

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
out_subpool_put:
2111
	if (map_chg || avoid_reserve)
2112
		hugepage_subpool_put_pages(spool, 1);
2113
	vma_end_reservation(h, vma, addr);
2114
	return ERR_PTR(-ENOSPC);
2115 2116
}

2117 2118 2119
int alloc_bootmem_huge_page(struct hstate *h)
	__attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
int __alloc_bootmem_huge_page(struct hstate *h)
2120 2121
{
	struct huge_bootmem_page *m;
2122
	int nr_nodes, node;
2123

2124
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2125 2126
		void *addr;

2127
		addr = memblock_alloc_try_nid_raw(
2128
				huge_page_size(h), huge_page_size(h),
2129
				0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2130 2131 2132 2133 2134 2135 2136
		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;
2137
			goto found;
2138 2139 2140 2141 2142
		}
	}
	return 0;

found:
2143
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2144
	/* Put them into a private list first because mem_map is not up yet */
2145
	INIT_LIST_HEAD(&m->list);
2146 2147 2148 2149 2150
	list_add(&m->list, &huge_boot_pages);
	m->hstate = h;
	return 1;
}

2151 2152
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
2153 2154 2155 2156 2157 2158 2159
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

2160 2161 2162 2163 2164 2165
/* 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) {
2166
		struct page *page = virt_to_page(m);
2167
		struct hstate *h = m->hstate;
2168

2169
		WARN_ON(page_count(page) != 1);
2170
		prep_compound_huge_page(page, h->order);
2171
		WARN_ON(PageReserved(page));
2172
		prep_new_huge_page(h, page, page_to_nid(page));
2173 2174
		put_page(page); /* free it into the hugepage allocator */

2175 2176 2177 2178 2179 2180
		/*
		 * 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.
		 */
2181
		if (hstate_is_gigantic(h))
2182
			adjust_managed_page_count(page, 1 << h->order);
2183
		cond_resched();
2184 2185 2186
	}
}

2187
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2188 2189
{
	unsigned long i;
2190

2191
	for (i = 0; i < h->max_huge_pages; ++i) {
2192
		if (hstate_is_gigantic(h)) {
2193 2194
			if (!alloc_bootmem_huge_page(h))
				break;
2195
		} else if (!alloc_pool_huge_page(h,
2196
					 &node_states[N_MEMORY]))
L
Linus Torvalds 已提交
2197
			break;
2198
		cond_resched();
L
Linus Torvalds 已提交
2199
	}
2200 2201 2202
	if (i < h->max_huge_pages) {
		char buf[32];

2203
		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2204 2205 2206 2207
		pr_warn("HugeTLB: allocating %lu of page size %s failed.  Only allocated %lu hugepages.\n",
			h->max_huge_pages, buf, i);
		h->max_huge_pages = i;
	}
2208 2209 2210 2211 2212 2213 2214
}

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

	for_each_hstate(h) {
2215 2216 2217
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2218
		/* oversize hugepages were init'ed in early boot */
2219
		if (!hstate_is_gigantic(h))
2220
			hugetlb_hstate_alloc_pages(h);
2221
	}
2222
	VM_BUG_ON(minimum_order == UINT_MAX);
2223 2224 2225 2226 2227 2228 2229
}

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

	for_each_hstate(h) {
A
Andi Kleen 已提交
2230
		char buf[32];
2231 2232

		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2233
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2234
			buf, h->free_huge_pages);
2235 2236 2237
	}
}

L
Linus Torvalds 已提交
2238
#ifdef CONFIG_HIGHMEM
2239 2240
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2241
{
2242 2243
	int i;

2244
	if (hstate_is_gigantic(h))
2245 2246
		return;

2247
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2248
		struct page *page, *next;
2249 2250 2251
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2252
				return;
L
Linus Torvalds 已提交
2253 2254 2255
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2256
			update_and_free_page(h, page);
2257 2258
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2259 2260 2261 2262
		}
	}
}
#else
2263 2264
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2265 2266 2267 2268
{
}
#endif

2269 2270 2271 2272 2273
/*
 * 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.
 */
2274 2275
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2276
{
2277
	int nr_nodes, node;
2278 2279 2280

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

2281 2282 2283 2284
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2285
		}
2286 2287 2288 2289 2290
	} 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;
2291
		}
2292 2293
	}
	return 0;
2294

2295 2296 2297 2298
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2299 2300
}

2301
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2302
static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2303
			      nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2304
{
2305
	unsigned long min_count, ret;
L
Linus Torvalds 已提交
2306

2307 2308
	spin_lock(&hugetlb_lock);

2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328
	/*
	 * Check for a node specific request.
	 * Changing node specific huge page count may require a corresponding
	 * change to the global count.  In any case, the passed node mask
	 * (nodes_allowed) will restrict alloc/free to the specified node.
	 */
	if (nid != NUMA_NO_NODE) {
		unsigned long old_count = count;

		count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
		/*
		 * User may have specified a large count value which caused the
		 * above calculation to overflow.  In this case, they wanted
		 * to allocate as many huge pages as possible.  Set count to
		 * largest possible value to align with their intention.
		 */
		if (count < old_count)
			count = ULONG_MAX;
	}

2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342
	/*
	 * Gigantic pages runtime allocation depend on the capability for large
	 * page range allocation.
	 * If the system does not provide this feature, return an error when
	 * the user tries to allocate gigantic pages but let the user free the
	 * boottime allocated gigantic pages.
	 */
	if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
		if (count > persistent_huge_pages(h)) {
			spin_unlock(&hugetlb_lock);
			return -EINVAL;
		}
		/* Fall through to decrease pool */
	}
2343

2344 2345 2346 2347
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2348
	 *
2349
	 * We might race with alloc_surplus_huge_page() here and be unable
2350 2351 2352 2353
	 * 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.
2354
	 */
2355
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2356
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2357 2358 2359
			break;
	}

2360
	while (count > persistent_huge_pages(h)) {
2361 2362 2363 2364 2365 2366
		/*
		 * 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);
2367 2368 2369 2370

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

2371
		ret = alloc_pool_huge_page(h, nodes_allowed);
2372 2373 2374 2375
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2376 2377 2378
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2379 2380 2381 2382 2383 2384 2385 2386
	}

	/*
	 * 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.
2387 2388 2389 2390
	 *
	 * 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
2391
	 * alloc_surplus_huge_page() is checking the global counter,
2392 2393 2394
	 * 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.
2395
	 */
2396
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2397
	min_count = max(count, min_count);
2398
	try_to_free_low(h, min_count, nodes_allowed);
2399
	while (min_count < persistent_huge_pages(h)) {
2400
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2401
			break;
2402
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2403
	}
2404
	while (count < persistent_huge_pages(h)) {
2405
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2406 2407 2408
			break;
	}
out:
2409
	h->max_huge_pages = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2410
	spin_unlock(&hugetlb_lock);
2411 2412

	return 0;
L
Linus Torvalds 已提交
2413 2414
}

2415 2416 2417 2418 2419 2420 2421 2422 2423 2424
#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];

2425 2426 2427
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2428 2429
{
	int i;
2430

2431
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2432 2433 2434
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2435
			return &hstates[i];
2436 2437 2438
		}

	return kobj_to_node_hstate(kobj, nidp);
2439 2440
}

2441
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2442 2443
					struct kobj_attribute *attr, char *buf)
{
2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454
	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);
2455
}
2456

2457 2458 2459
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2460 2461
{
	int err;
2462
	nodemask_t nodes_allowed, *n_mask;
2463

2464 2465
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
		return -EINVAL;
2466

2467 2468 2469 2470 2471
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
2472 2473 2474 2475 2476
				init_nodemask_of_mempolicy(&nodes_allowed)))
			n_mask = &node_states[N_MEMORY];
		else
			n_mask = &nodes_allowed;
	} else {
2477
		/*
2478 2479
		 * Node specific request.  count adjustment happens in
		 * set_max_huge_pages() after acquiring hugetlb_lock.
2480
		 */
2481 2482
		init_nodemask_of_node(&nodes_allowed, nid);
		n_mask = &nodes_allowed;
2483
	}
2484

2485
	err = set_max_huge_pages(h, count, nid, n_mask);
2486

2487
	return err ? err : len;
2488 2489
}

2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506
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);
}

2507 2508 2509 2510 2511 2512 2513 2514 2515
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)
{
2516
	return nr_hugepages_store_common(false, kobj, buf, len);
2517 2518 2519
}
HSTATE_ATTR(nr_hugepages);

2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534
#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)
{
2535
	return nr_hugepages_store_common(true, kobj, buf, len);
2536 2537 2538 2539 2540
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2541 2542 2543
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2544
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2545 2546
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2547

2548 2549 2550 2551 2552
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;
2553
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2554

2555
	if (hstate_is_gigantic(h))
2556 2557
		return -EINVAL;

2558
	err = kstrtoul(buf, 10, &input);
2559
	if (err)
2560
		return err;
2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572

	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)
{
2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583
	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);
2584 2585 2586 2587 2588 2589
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2590
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2591 2592 2593 2594 2595 2596 2597
	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)
{
2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608
	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);
2609 2610 2611 2612 2613 2614 2615 2616 2617
}
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,
2618 2619 2620
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
2621 2622 2623
	NULL,
};

2624
static const struct attribute_group hstate_attr_group = {
2625 2626 2627
	.attrs = hstate_attrs,
};

J
Jeff Mahoney 已提交
2628 2629
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
2630
				    const struct attribute_group *hstate_attr_group)
2631 2632
{
	int retval;
2633
	int hi = hstate_index(h);
2634

2635 2636
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
2637 2638
		return -ENOMEM;

2639
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2640
	if (retval)
2641
		kobject_put(hstate_kobjs[hi]);
2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655

	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) {
2656 2657
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
2658
		if (err)
2659
			pr_err("Hugetlb: Unable to add hstate %s", h->name);
2660 2661 2662
	}
}

2663 2664 2665 2666
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2667 2668 2669
 * 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
2670 2671 2672 2673 2674 2675
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
2676
static struct node_hstate node_hstates[MAX_NUMNODES];
2677 2678

/*
2679
 * A subset of global hstate attributes for node devices
2680 2681 2682 2683 2684 2685 2686 2687
 */
static struct attribute *per_node_hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
	NULL,
};

2688
static const struct attribute_group per_node_hstate_attr_group = {
2689 2690 2691 2692
	.attrs = per_node_hstate_attrs,
};

/*
2693
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715
 * 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;
}

/*
2716
 * Unregister hstate attributes from a single node device.
2717 2718
 * No-op if no hstate attributes attached.
 */
2719
static void hugetlb_unregister_node(struct node *node)
2720 2721
{
	struct hstate *h;
2722
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2723 2724

	if (!nhs->hugepages_kobj)
2725
		return;		/* no hstate attributes */
2726

2727 2728 2729 2730 2731
	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;
2732
		}
2733
	}
2734 2735 2736 2737 2738 2739 2740

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


/*
2741
 * Register hstate attributes for a single node device.
2742 2743
 * No-op if attributes already registered.
 */
2744
static void hugetlb_register_node(struct node *node)
2745 2746
{
	struct hstate *h;
2747
	struct node_hstate *nhs = &node_hstates[node->dev.id];
2748 2749 2750 2751 2752 2753
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
2754
							&node->dev.kobj);
2755 2756 2757 2758 2759 2760 2761 2762
	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) {
2763 2764
			pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
				h->name, node->dev.id);
2765 2766 2767 2768 2769 2770 2771
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
2772
 * hugetlb init time:  register hstate attributes for all registered node
2773 2774
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
2775
 */
2776
static void __init hugetlb_register_all_nodes(void)
2777 2778 2779
{
	int nid;

2780
	for_each_node_state(nid, N_MEMORY) {
2781
		struct node *node = node_devices[nid];
2782
		if (node->dev.id == nid)
2783 2784 2785 2786
			hugetlb_register_node(node);
	}

	/*
2787
	 * Let the node device driver know we're here so it can
2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806
	 * [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

2807 2808
static int __init hugetlb_init(void)
{
2809 2810
	int i;

2811
	if (!hugepages_supported())
2812
		return 0;
2813

2814
	if (!size_to_hstate(default_hstate_size)) {
2815 2816 2817 2818 2819
		if (default_hstate_size != 0) {
			pr_err("HugeTLB: unsupported default_hugepagesz %lu. Reverting to %lu\n",
			       default_hstate_size, HPAGE_SIZE);
		}

2820 2821 2822
		default_hstate_size = HPAGE_SIZE;
		if (!size_to_hstate(default_hstate_size))
			hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
2823
	}
2824
	default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size));
2825 2826 2827 2828
	if (default_hstate_max_huge_pages) {
		if (!default_hstate.max_huge_pages)
			default_hstate.max_huge_pages = default_hstate_max_huge_pages;
	}
2829 2830

	hugetlb_init_hstates();
2831
	gather_bootmem_prealloc();
2832 2833 2834
	report_hugepages();

	hugetlb_sysfs_init();
2835
	hugetlb_register_all_nodes();
2836
	hugetlb_cgroup_file_init();
2837

2838 2839 2840 2841 2842
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
2843
	hugetlb_fault_mutex_table =
2844 2845
		kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
			      GFP_KERNEL);
2846
	BUG_ON(!hugetlb_fault_mutex_table);
2847 2848

	for (i = 0; i < num_fault_mutexes; i++)
2849
		mutex_init(&hugetlb_fault_mutex_table[i]);
2850 2851
	return 0;
}
2852
subsys_initcall(hugetlb_init);
2853 2854

/* Should be called on processing a hugepagesz=... option */
2855 2856 2857 2858 2859
void __init hugetlb_bad_size(void)
{
	parsed_valid_hugepagesz = false;
}

2860
void __init hugetlb_add_hstate(unsigned int order)
2861 2862
{
	struct hstate *h;
2863 2864
	unsigned long i;

2865
	if (size_to_hstate(PAGE_SIZE << order)) {
J
Joe Perches 已提交
2866
		pr_warn("hugepagesz= specified twice, ignoring\n");
2867 2868
		return;
	}
2869
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
2870
	BUG_ON(order == 0);
2871
	h = &hstates[hugetlb_max_hstate++];
2872 2873
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
2874 2875 2876 2877
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
2878
	INIT_LIST_HEAD(&h->hugepage_activelist);
2879 2880
	h->next_nid_to_alloc = first_memory_node;
	h->next_nid_to_free = first_memory_node;
2881 2882
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
2883

2884 2885 2886
	parsed_hstate = h;
}

2887
static int __init hugetlb_nrpages_setup(char *s)
2888 2889
{
	unsigned long *mhp;
2890
	static unsigned long *last_mhp;
2891

2892 2893 2894 2895 2896 2897
	if (!parsed_valid_hugepagesz) {
		pr_warn("hugepages = %s preceded by "
			"an unsupported hugepagesz, ignoring\n", s);
		parsed_valid_hugepagesz = true;
		return 1;
	}
2898
	/*
2899
	 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
2900 2901
	 * so this hugepages= parameter goes to the "default hstate".
	 */
2902
	else if (!hugetlb_max_hstate)
2903 2904 2905 2906
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

2907
	if (mhp == last_mhp) {
J
Joe Perches 已提交
2908
		pr_warn("hugepages= specified twice without interleaving hugepagesz=, ignoring\n");
2909 2910 2911
		return 1;
	}

2912 2913 2914
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

2915 2916 2917 2918 2919
	/*
	 * 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.
	 */
2920
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
2921 2922 2923 2924
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

2925 2926
	return 1;
}
2927 2928 2929 2930 2931 2932 2933 2934
__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);
2935

2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947
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
2948 2949 2950
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
2951
{
2952
	struct hstate *h = &default_hstate;
2953
	unsigned long tmp = h->max_huge_pages;
2954
	int ret;
2955

2956
	if (!hugepages_supported())
2957
		return -EOPNOTSUPP;
2958

2959 2960
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
2961 2962 2963
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
2964

2965 2966 2967
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
2968 2969
out:
	return ret;
L
Linus Torvalds 已提交
2970
}
2971

2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988
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 */

2989
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
2990
			void __user *buffer,
2991 2992
			size_t *length, loff_t *ppos)
{
2993
	struct hstate *h = &default_hstate;
2994
	unsigned long tmp;
2995
	int ret;
2996

2997
	if (!hugepages_supported())
2998
		return -EOPNOTSUPP;
2999

3000
	tmp = h->nr_overcommit_huge_pages;
3001

3002
	if (write && hstate_is_gigantic(h))
3003 3004
		return -EINVAL;

3005 3006
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
3007 3008 3009
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
3010 3011 3012 3013 3014 3015

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
3016 3017
out:
	return ret;
3018 3019
}

L
Linus Torvalds 已提交
3020 3021
#endif /* CONFIG_SYSCTL */

3022
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
3023
{
3024 3025 3026
	struct hstate *h;
	unsigned long total = 0;

3027 3028
	if (!hugepages_supported())
		return;
3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049

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

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

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

	seq_printf(m, "Hugetlb:        %8lu kB\n", total / 1024);
L
Linus Torvalds 已提交
3050 3051 3052 3053
}

int hugetlb_report_node_meminfo(int nid, char *buf)
{
3054
	struct hstate *h = &default_hstate;
3055 3056
	if (!hugepages_supported())
		return 0;
L
Linus Torvalds 已提交
3057 3058
	return sprintf(buf,
		"Node %d HugePages_Total: %5u\n"
3059 3060
		"Node %d HugePages_Free:  %5u\n"
		"Node %d HugePages_Surp:  %5u\n",
3061 3062 3063
		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
3064 3065
}

3066 3067 3068 3069 3070
void hugetlb_show_meminfo(void)
{
	struct hstate *h;
	int nid;

3071 3072 3073
	if (!hugepages_supported())
		return;

3074 3075 3076 3077 3078 3079 3080 3081 3082 3083
	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));
}

3084 3085 3086 3087 3088 3089
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
3090 3091 3092
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
3093 3094 3095 3096 3097 3098
	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
3099 3100
}

3101
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123
{
	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) {
3124
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
3125 3126
			goto out;

3127 3128
		if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
3129 3130 3131 3132 3133 3134
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
3135
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
3136 3137 3138 3139 3140 3141

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

3142 3143
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
3144
	struct resv_map *resv = vma_resv_map(vma);
3145 3146 3147 3148 3149

	/*
	 * 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
3150
	 * has a reference to the reservation map it cannot disappear until
3151 3152 3153
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
3154
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3155
		kref_get(&resv->refs);
3156 3157
}

3158 3159
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
3160
	struct hstate *h = hstate_vma(vma);
3161
	struct resv_map *resv = vma_resv_map(vma);
3162
	struct hugepage_subpool *spool = subpool_vma(vma);
3163
	unsigned long reserve, start, end;
3164
	long gbl_reserve;
3165

3166 3167
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
3168

3169 3170
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
3171

3172
	reserve = (end - start) - region_count(resv, start, end);
3173

3174 3175 3176
	kref_put(&resv->refs, resv_map_release);

	if (reserve) {
3177 3178 3179 3180 3181 3182
		/*
		 * 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);
3183
	}
3184 3185
}

3186 3187 3188 3189 3190 3191 3192
static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
{
	if (addr & ~(huge_page_mask(hstate_vma(vma))))
		return -EINVAL;
	return 0;
}

3193 3194 3195 3196 3197 3198 3199
static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
{
	struct hstate *hstate = hstate_vma(vma);

	return 1UL << huge_page_shift(hstate);
}

L
Linus Torvalds 已提交
3200 3201 3202 3203 3204 3205
/*
 * 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.
 */
3206
static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
L
Linus Torvalds 已提交
3207 3208
{
	BUG();
N
Nick Piggin 已提交
3209
	return 0;
L
Linus Torvalds 已提交
3210 3211
}

3212 3213 3214 3215 3216 3217 3218
/*
 * When a new function is introduced to vm_operations_struct and added
 * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
 * This is because under System V memory model, mappings created via
 * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
 * their original vm_ops are overwritten with shm_vm_ops.
 */
3219
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
3220
	.fault = hugetlb_vm_op_fault,
3221
	.open = hugetlb_vm_op_open,
3222
	.close = hugetlb_vm_op_close,
3223
	.split = hugetlb_vm_op_split,
3224
	.pagesize = hugetlb_vm_op_pagesize,
L
Linus Torvalds 已提交
3225 3226
};

3227 3228
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
3229 3230 3231
{
	pte_t entry;

3232
	if (writable) {
3233 3234
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
3235
	} else {
3236 3237
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
3238 3239 3240
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3241
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3242 3243 3244 3245

	return entry;
}

3246 3247 3248 3249 3250
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3251
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3252
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3253
		update_mmu_cache(vma, address, ptep);
3254 3255
}

3256
bool is_hugetlb_entry_migration(pte_t pte)
3257 3258 3259 3260
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3261
		return false;
3262 3263
	swp = pte_to_swp_entry(pte);
	if (non_swap_entry(swp) && is_migration_entry(swp))
3264
		return true;
3265
	else
3266
		return false;
3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280
}

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;
}
3281

D
David Gibson 已提交
3282 3283 3284
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
			    struct vm_area_struct *vma)
{
3285
	pte_t *src_pte, *dst_pte, entry, dst_entry;
D
David Gibson 已提交
3286
	struct page *ptepage;
3287
	unsigned long addr;
3288
	int cow;
3289 3290
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3291
	struct mmu_notifier_range range;
3292
	int ret = 0;
3293 3294

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3295

3296 3297 3298 3299 3300
	if (cow) {
		mmu_notifier_range_init(&range, src, vma->vm_start,
					vma->vm_end);
		mmu_notifier_invalidate_range_start(&range);
	}
3301

3302
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3303
		spinlock_t *src_ptl, *dst_ptl;
3304
		src_pte = huge_pte_offset(src, addr, sz);
H
Hugh Dickins 已提交
3305 3306
		if (!src_pte)
			continue;
3307
		dst_pte = huge_pte_alloc(dst, addr, sz);
3308 3309 3310 3311
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3312

3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323
		/*
		 * If the pagetables are shared don't copy or take references.
		 * dst_pte == src_pte is the common case of src/dest sharing.
		 *
		 * However, src could have 'unshared' and dst shares with
		 * another vma.  If dst_pte !none, this implies sharing.
		 * Check here before taking page table lock, and once again
		 * after taking the lock below.
		 */
		dst_entry = huge_ptep_get(dst_pte);
		if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
3324 3325
			continue;

3326 3327 3328
		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);
3329
		entry = huge_ptep_get(src_pte);
3330 3331 3332 3333 3334 3335 3336
		dst_entry = huge_ptep_get(dst_pte);
		if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
			/*
			 * Skip if src entry none.  Also, skip in the
			 * unlikely case dst entry !none as this implies
			 * sharing with another vma.
			 */
3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348
			;
		} 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);
3349 3350
				set_huge_swap_pte_at(src, addr, src_pte,
						     entry, sz);
3351
			}
3352
			set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3353
		} else {
3354
			if (cow) {
3355 3356 3357 3358 3359
				/*
				 * No need to notify as we are downgrading page
				 * table protection not changing it to point
				 * to a new page.
				 *
3360
				 * See Documentation/vm/mmu_notifier.rst
3361
				 */
3362
				huge_ptep_set_wrprotect(src, addr, src_pte);
3363
			}
3364
			entry = huge_ptep_get(src_pte);
3365 3366
			ptepage = pte_page(entry);
			get_page(ptepage);
3367
			page_dup_rmap(ptepage, true);
3368
			set_huge_pte_at(dst, addr, dst_pte, entry);
3369
			hugetlb_count_add(pages_per_huge_page(h), dst);
3370
		}
3371 3372
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3373 3374
	}

3375
	if (cow)
3376
		mmu_notifier_invalidate_range_end(&range);
3377 3378

	return ret;
D
David Gibson 已提交
3379 3380
}

3381 3382 3383
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
3384 3385 3386
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3387
	pte_t *ptep;
D
David Gibson 已提交
3388
	pte_t pte;
3389
	spinlock_t *ptl;
D
David Gibson 已提交
3390
	struct page *page;
3391 3392
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3393
	struct mmu_notifier_range range;
3394

D
David Gibson 已提交
3395
	WARN_ON(!is_vm_hugetlb_page(vma));
3396 3397
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3398

3399 3400 3401 3402
	/*
	 * This is a hugetlb vma, all the pte entries should point
	 * to huge page.
	 */
3403
	tlb_change_page_size(tlb, sz);
3404
	tlb_start_vma(tlb, vma);
3405 3406 3407 3408

	/*
	 * If sharing possible, alert mmu notifiers of worst case.
	 */
3409 3410 3411
	mmu_notifier_range_init(&range, mm, start, end);
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
	mmu_notifier_invalidate_range_start(&range);
3412 3413
	address = start;
	for (; address < end; address += sz) {
3414
		ptep = huge_pte_offset(mm, address, sz);
A
Adam Litke 已提交
3415
		if (!ptep)
3416 3417
			continue;

3418
		ptl = huge_pte_lock(h, mm, ptep);
3419 3420
		if (huge_pmd_unshare(mm, &address, ptep)) {
			spin_unlock(ptl);
3421 3422 3423 3424
			/*
			 * We just unmapped a page of PMDs by clearing a PUD.
			 * The caller's TLB flush range should cover this area.
			 */
3425 3426
			continue;
		}
3427

3428
		pte = huge_ptep_get(ptep);
3429 3430 3431 3432
		if (huge_pte_none(pte)) {
			spin_unlock(ptl);
			continue;
		}
3433 3434

		/*
3435 3436
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3437
		 */
3438
		if (unlikely(!pte_present(pte))) {
3439
			huge_pte_clear(mm, address, ptep, sz);
3440 3441
			spin_unlock(ptl);
			continue;
3442
		}
3443 3444

		page = pte_page(pte);
3445 3446 3447 3448 3449 3450
		/*
		 * 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) {
3451 3452 3453 3454
			if (page != ref_page) {
				spin_unlock(ptl);
				continue;
			}
3455 3456 3457 3458 3459 3460 3461 3462
			/*
			 * 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);
		}

3463
		pte = huge_ptep_get_and_clear(mm, address, ptep);
3464
		tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3465
		if (huge_pte_dirty(pte))
3466
			set_page_dirty(page);
3467

3468
		hugetlb_count_sub(pages_per_huge_page(h), mm);
3469
		page_remove_rmap(page, true);
3470

3471
		spin_unlock(ptl);
3472
		tlb_remove_page_size(tlb, page, huge_page_size(h));
3473 3474 3475 3476 3477
		/*
		 * Bail out after unmapping reference page if supplied
		 */
		if (ref_page)
			break;
3478
	}
3479
	mmu_notifier_invalidate_range_end(&range);
3480
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
3481
}
D
David Gibson 已提交
3482

3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494
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
3495
	 * is to clear it before releasing the i_mmap_rwsem. This works
3496
	 * because in the context this is called, the VMA is about to be
3497
	 * destroyed and the i_mmap_rwsem is held.
3498 3499 3500 3501
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

3502
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3503
			  unsigned long end, struct page *ref_page)
3504
{
3505 3506
	struct mm_struct *mm;
	struct mmu_gather tlb;
3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517
	unsigned long tlb_start = start;
	unsigned long tlb_end = end;

	/*
	 * If shared PMDs were possibly used within this vma range, adjust
	 * start/end for worst case tlb flushing.
	 * Note that we can not be sure if PMDs are shared until we try to
	 * unmap pages.  However, we want to make sure TLB flushing covers
	 * the largest possible range.
	 */
	adjust_range_if_pmd_sharing_possible(vma, &tlb_start, &tlb_end);
3518 3519 3520

	mm = vma->vm_mm;

3521
	tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end);
3522
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
3523
	tlb_finish_mmu(&tlb, tlb_start, tlb_end);
3524 3525
}

3526 3527 3528 3529 3530 3531
/*
 * 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.
 */
3532 3533
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
3534
{
3535
	struct hstate *h = hstate_vma(vma);
3536 3537 3538 3539 3540 3541 3542 3543
	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.
	 */
3544
	address = address & huge_page_mask(h);
3545 3546
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
3547
	mapping = vma->vm_file->f_mapping;
3548

3549 3550 3551 3552 3553
	/*
	 * 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
	 */
3554
	i_mmap_lock_write(mapping);
3555
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
3556 3557 3558 3559
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

3560 3561 3562 3563 3564 3565 3566 3567
		/*
		 * 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;

3568 3569 3570 3571 3572 3573 3574 3575
		/*
		 * 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))
3576 3577
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
3578
	}
3579
	i_mmap_unlock_write(mapping);
3580 3581
}

3582 3583
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
3584 3585 3586
 * 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.
3587
 */
3588
static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
3589
		       unsigned long address, pte_t *ptep,
3590
		       struct page *pagecache_page, spinlock_t *ptl)
3591
{
3592
	pte_t pte;
3593
	struct hstate *h = hstate_vma(vma);
3594
	struct page *old_page, *new_page;
3595 3596
	int outside_reserve = 0;
	vm_fault_t ret = 0;
3597
	unsigned long haddr = address & huge_page_mask(h);
3598
	struct mmu_notifier_range range;
3599

3600
	pte = huge_ptep_get(ptep);
3601 3602
	old_page = pte_page(pte);

3603
retry_avoidcopy:
3604 3605
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
3606
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
3607
		page_move_anon_rmap(old_page, vma);
3608
		set_huge_ptep_writable(vma, haddr, ptep);
N
Nick Piggin 已提交
3609
		return 0;
3610 3611
	}

3612 3613 3614 3615 3616 3617 3618 3619 3620
	/*
	 * 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.
	 */
3621
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
3622 3623 3624
			old_page != pagecache_page)
		outside_reserve = 1;

3625
	get_page(old_page);
3626

3627 3628 3629 3630
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
3631
	spin_unlock(ptl);
3632
	new_page = alloc_huge_page(vma, haddr, outside_reserve);
3633

3634
	if (IS_ERR(new_page)) {
3635 3636 3637 3638 3639 3640 3641 3642
		/*
		 * 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) {
3643
			put_page(old_page);
3644
			BUG_ON(huge_pte_none(pte));
3645
			unmap_ref_private(mm, vma, old_page, haddr);
3646 3647
			BUG_ON(huge_pte_none(pte));
			spin_lock(ptl);
3648
			ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
3649 3650 3651 3652 3653 3654 3655 3656
			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;
3657 3658
		}

3659
		ret = vmf_error(PTR_ERR(new_page));
3660
		goto out_release_old;
3661 3662
	}

3663 3664 3665 3666
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
3667
	if (unlikely(anon_vma_prepare(vma))) {
3668 3669
		ret = VM_FAULT_OOM;
		goto out_release_all;
3670
	}
3671

3672
	copy_user_huge_page(new_page, old_page, address, vma,
A
Andrea Arcangeli 已提交
3673
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
3674
	__SetPageUptodate(new_page);
3675

3676 3677
	mmu_notifier_range_init(&range, mm, haddr, haddr + huge_page_size(h));
	mmu_notifier_invalidate_range_start(&range);
3678

3679
	/*
3680
	 * Retake the page table lock to check for racing updates
3681 3682
	 * before the page tables are altered
	 */
3683
	spin_lock(ptl);
3684
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
3685
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
3686 3687
		ClearPagePrivate(new_page);

3688
		/* Break COW */
3689
		huge_ptep_clear_flush(vma, haddr, ptep);
3690
		mmu_notifier_invalidate_range(mm, range.start, range.end);
3691
		set_huge_pte_at(mm, haddr, ptep,
3692
				make_huge_pte(vma, new_page, 1));
3693
		page_remove_rmap(old_page, true);
3694
		hugepage_add_new_anon_rmap(new_page, vma, haddr);
3695
		set_page_huge_active(new_page);
3696 3697 3698
		/* Make the old page be freed below */
		new_page = old_page;
	}
3699
	spin_unlock(ptl);
3700
	mmu_notifier_invalidate_range_end(&range);
3701
out_release_all:
3702
	restore_reserve_on_error(h, vma, haddr, new_page);
3703
	put_page(new_page);
3704
out_release_old:
3705
	put_page(old_page);
3706

3707 3708
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
3709 3710
}

3711
/* Return the pagecache page at a given address within a VMA */
3712 3713
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
3714 3715
{
	struct address_space *mapping;
3716
	pgoff_t idx;
3717 3718

	mapping = vma->vm_file->f_mapping;
3719
	idx = vma_hugecache_offset(h, vma, address);
3720 3721 3722 3723

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
3724 3725 3726 3727 3728
/*
 * 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
3729 3730 3731 3732 3733 3734 3735 3736 3737 3738 3739 3740 3741 3742 3743
			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;
}

3744 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754
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);

3755 3756 3757 3758 3759 3760
	/*
	 * set page dirty so that it will not be removed from cache/file
	 * by non-hugetlbfs specific code paths.
	 */
	set_page_dirty(page);

3761 3762 3763 3764 3765 3766
	spin_lock(&inode->i_lock);
	inode->i_blocks += blocks_per_huge_page(h);
	spin_unlock(&inode->i_lock);
	return 0;
}

3767 3768 3769 3770
static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
			struct vm_area_struct *vma,
			struct address_space *mapping, pgoff_t idx,
			unsigned long address, pte_t *ptep, unsigned int flags)
3771
{
3772
	struct hstate *h = hstate_vma(vma);
3773
	vm_fault_t ret = VM_FAULT_SIGBUS;
3774
	int anon_rmap = 0;
A
Adam Litke 已提交
3775 3776
	unsigned long size;
	struct page *page;
3777
	pte_t new_pte;
3778
	spinlock_t *ptl;
3779
	unsigned long haddr = address & huge_page_mask(h);
3780
	bool new_page = false;
A
Adam Litke 已提交
3781

3782 3783 3784
	/*
	 * 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
3785
	 * COW. Warn that such a situation has occurred as it may not be obvious
3786 3787
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
3788
		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
3789
			   current->pid);
3790 3791 3792
		return ret;
	}

A
Adam Litke 已提交
3793
	/*
3794 3795
	 * Use page lock to guard against racing truncation
	 * before we get page_table_lock.
A
Adam Litke 已提交
3796
	 */
3797 3798 3799
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
3800 3801 3802 3803
		size = i_size_read(mapping->host) >> huge_page_shift(h);
		if (idx >= size)
			goto out;

3804 3805 3806 3807 3808 3809 3810
		/*
		 * Check for page in userfault range
		 */
		if (userfaultfd_missing(vma)) {
			u32 hash;
			struct vm_fault vmf = {
				.vma = vma,
3811
				.address = haddr,
3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822
				.flags = flags,
				/*
				 * Hard to debug if it ends up being
				 * used by a callee that assumes
				 * something about the other
				 * uninitialized fields... same as in
				 * memory.c
				 */
			};

			/*
3823 3824 3825
			 * hugetlb_fault_mutex must be dropped before
			 * handling userfault.  Reacquire after handling
			 * fault to make calling code simpler.
3826 3827
			 */
			hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping,
3828
							idx, haddr);
3829 3830 3831 3832 3833 3834
			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
			ret = handle_userfault(&vmf, VM_UFFD_MISSING);
			mutex_lock(&hugetlb_fault_mutex_table[hash]);
			goto out;
		}

3835
		page = alloc_huge_page(vma, haddr, 0);
3836
		if (IS_ERR(page)) {
3837
			ret = vmf_error(PTR_ERR(page));
3838 3839
			goto out;
		}
A
Andrea Arcangeli 已提交
3840
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
3841
		__SetPageUptodate(page);
3842
		new_page = true;
3843

3844
		if (vma->vm_flags & VM_MAYSHARE) {
3845
			int err = huge_add_to_page_cache(page, mapping, idx);
3846 3847 3848 3849 3850 3851
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
3852
		} else {
3853
			lock_page(page);
3854 3855 3856 3857
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
3858
			anon_rmap = 1;
3859
		}
3860
	} else {
3861 3862 3863 3864 3865 3866
		/*
		 * 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))) {
3867
			ret = VM_FAULT_HWPOISON |
3868
				VM_FAULT_SET_HINDEX(hstate_index(h));
3869 3870
			goto backout_unlocked;
		}
3871
	}
3872

3873 3874 3875 3876 3877 3878
	/*
	 * 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.
	 */
3879
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3880
		if (vma_needs_reservation(h, vma, haddr) < 0) {
3881 3882 3883
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
3884
		/* Just decrements count, does not deallocate */
3885
		vma_end_reservation(h, vma, haddr);
3886
	}
3887

3888
	ptl = huge_pte_lock(h, mm, ptep);
3889 3890 3891
	size = i_size_read(mapping->host) >> huge_page_shift(h);
	if (idx >= size)
		goto backout;
A
Adam Litke 已提交
3892

N
Nick Piggin 已提交
3893
	ret = 0;
3894
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
3895 3896
		goto backout;

3897 3898
	if (anon_rmap) {
		ClearPagePrivate(page);
3899
		hugepage_add_new_anon_rmap(page, vma, haddr);
3900
	} else
3901
		page_dup_rmap(page, true);
3902 3903
	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
				&& (vma->vm_flags & VM_SHARED)));
3904
	set_huge_pte_at(mm, haddr, ptep, new_pte);
3905

3906
	hugetlb_count_add(pages_per_huge_page(h), mm);
3907
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3908
		/* Optimization, do the COW without a second fault */
3909
		ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
3910 3911
	}

3912
	spin_unlock(ptl);
3913 3914 3915 3916 3917 3918 3919 3920 3921

	/*
	 * Only make newly allocated pages active.  Existing pages found
	 * in the pagecache could be !page_huge_active() if they have been
	 * isolated for migration.
	 */
	if (new_page)
		set_page_huge_active(page);

A
Adam Litke 已提交
3922 3923
	unlock_page(page);
out:
3924
	return ret;
A
Adam Litke 已提交
3925 3926

backout:
3927
	spin_unlock(ptl);
3928
backout_unlocked:
A
Adam Litke 已提交
3929
	unlock_page(page);
3930
	restore_reserve_on_error(h, vma, haddr, page);
A
Adam Litke 已提交
3931 3932
	put_page(page);
	goto out;
3933 3934
}

3935
#ifdef CONFIG_SMP
3936
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3937 3938 3939 3940 3941 3942 3943 3944 3945 3946 3947 3948 3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960
			    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.
 */
3961
u32 hugetlb_fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
3962 3963 3964 3965 3966 3967 3968 3969
			    struct vm_area_struct *vma,
			    struct address_space *mapping,
			    pgoff_t idx, unsigned long address)
{
	return 0;
}
#endif

3970
vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3971
			unsigned long address, unsigned int flags)
3972
{
3973
	pte_t *ptep, entry;
3974
	spinlock_t *ptl;
3975
	vm_fault_t ret;
3976 3977
	u32 hash;
	pgoff_t idx;
3978
	struct page *page = NULL;
3979
	struct page *pagecache_page = NULL;
3980
	struct hstate *h = hstate_vma(vma);
3981
	struct address_space *mapping;
3982
	int need_wait_lock = 0;
3983
	unsigned long haddr = address & huge_page_mask(h);
3984

3985
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
3986 3987
	if (ptep) {
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
3988
		if (unlikely(is_hugetlb_entry_migration(entry))) {
3989
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
3990 3991
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
3992
			return VM_FAULT_HWPOISON_LARGE |
3993
				VM_FAULT_SET_HINDEX(hstate_index(h));
3994 3995 3996 3997
	} else {
		ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
		if (!ptep)
			return VM_FAULT_OOM;
3998 3999
	}

4000
	mapping = vma->vm_file->f_mapping;
4001
	idx = vma_hugecache_offset(h, vma, haddr);
4002

4003 4004 4005 4006 4007
	/*
	 * 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.
	 */
4008
	hash = hugetlb_fault_mutex_hash(h, mm, vma, mapping, idx, haddr);
4009
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
4010

4011 4012
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
4013
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4014
		goto out_mutex;
4015
	}
4016

N
Nick Piggin 已提交
4017
	ret = 0;
4018

4019 4020 4021 4022 4023 4024 4025 4026 4027 4028
	/*
	 * 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;

4029 4030 4031 4032 4033 4034 4035 4036
	/*
	 * 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.
	 */
4037
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4038
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4039
			ret = VM_FAULT_OOM;
4040
			goto out_mutex;
4041
		}
4042
		/* Just decrements count, does not deallocate */
4043
		vma_end_reservation(h, vma, haddr);
4044

4045
		if (!(vma->vm_flags & VM_MAYSHARE))
4046
			pagecache_page = hugetlbfs_pagecache_page(h,
4047
								vma, haddr);
4048 4049
	}

4050 4051 4052 4053 4054 4055
	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;

4056 4057 4058 4059 4060 4061 4062
	/*
	 * 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)
4063 4064 4065 4066
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
4067

4068
	get_page(page);
4069

4070
	if (flags & FAULT_FLAG_WRITE) {
4071
		if (!huge_pte_write(entry)) {
4072
			ret = hugetlb_cow(mm, vma, address, ptep,
4073
					  pagecache_page, ptl);
4074
			goto out_put_page;
4075
		}
4076
		entry = huge_pte_mkdirty(entry);
4077 4078
	}
	entry = pte_mkyoung(entry);
4079
	if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4080
						flags & FAULT_FLAG_WRITE))
4081
		update_mmu_cache(vma, haddr, ptep);
4082 4083 4084 4085
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
4086 4087
out_ptl:
	spin_unlock(ptl);
4088 4089 4090 4091 4092

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
4093
out_mutex:
4094
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4095 4096 4097 4098 4099 4100 4101 4102 4103
	/*
	 * 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);
4104
	return ret;
4105 4106
}

4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117
/*
 * Used by userfaultfd UFFDIO_COPY.  Based on mcopy_atomic_pte with
 * modifications for huge pages.
 */
int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
			    pte_t *dst_pte,
			    struct vm_area_struct *dst_vma,
			    unsigned long dst_addr,
			    unsigned long src_addr,
			    struct page **pagep)
{
4118 4119 4120
	struct address_space *mapping;
	pgoff_t idx;
	unsigned long size;
4121
	int vm_shared = dst_vma->vm_flags & VM_SHARED;
4122 4123 4124 4125 4126 4127 4128 4129 4130 4131 4132 4133 4134 4135
	struct hstate *h = hstate_vma(dst_vma);
	pte_t _dst_pte;
	spinlock_t *ptl;
	int ret;
	struct page *page;

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

		ret = copy_huge_page_from_user(page,
						(const void __user *) src_addr,
4136
						pages_per_huge_page(h), false);
4137 4138 4139

		/* fallback to copy_from_user outside mmap_sem */
		if (unlikely(ret)) {
4140
			ret = -ENOENT;
4141 4142 4143 4144 4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156
			*pagep = page;
			/* don't free the page */
			goto out;
		}
	} else {
		page = *pagep;
		*pagep = NULL;
	}

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

4157 4158 4159
	mapping = dst_vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, dst_vma, dst_addr);

4160 4161 4162 4163
	/*
	 * If shared, add to page cache
	 */
	if (vm_shared) {
4164 4165 4166 4167
		size = i_size_read(mapping->host) >> huge_page_shift(h);
		ret = -EFAULT;
		if (idx >= size)
			goto out_release_nounlock;
4168

4169 4170 4171 4172 4173 4174
		/*
		 * Serialization between remove_inode_hugepages() and
		 * huge_add_to_page_cache() below happens through the
		 * hugetlb_fault_mutex_table that here must be hold by
		 * the caller.
		 */
4175 4176 4177 4178 4179
		ret = huge_add_to_page_cache(page, mapping, idx);
		if (ret)
			goto out_release_nounlock;
	}

4180 4181 4182
	ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
	spin_lock(ptl);

4183 4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196
	/*
	 * Recheck the i_size after holding PT lock to make sure not
	 * to leave any page mapped (as page_mapped()) beyond the end
	 * of the i_size (remove_inode_hugepages() is strict about
	 * enforcing that). If we bail out here, we'll also leave a
	 * page in the radix tree in the vm_shared case beyond the end
	 * of the i_size, but remove_inode_hugepages() will take care
	 * of it as soon as we drop the hugetlb_fault_mutex_table.
	 */
	size = i_size_read(mapping->host) >> huge_page_shift(h);
	ret = -EFAULT;
	if (idx >= size)
		goto out_release_unlock;

4197 4198 4199 4200
	ret = -EEXIST;
	if (!huge_pte_none(huge_ptep_get(dst_pte)))
		goto out_release_unlock;

4201 4202 4203 4204 4205 4206
	if (vm_shared) {
		page_dup_rmap(page, true);
	} else {
		ClearPagePrivate(page);
		hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
	}
4207 4208 4209 4210 4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221 4222

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

	set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);

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

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

	spin_unlock(ptl);
4223
	set_page_huge_active(page);
4224 4225
	if (vm_shared)
		unlock_page(page);
4226 4227 4228 4229 4230
	ret = 0;
out:
	return ret;
out_release_unlock:
	spin_unlock(ptl);
4231 4232
	if (vm_shared)
		unlock_page(page);
4233
out_release_nounlock:
4234 4235 4236 4237
	put_page(page);
	goto out;
}

4238 4239 4240
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,
4241
			 long i, unsigned int flags, int *nonblocking)
D
David Gibson 已提交
4242
{
4243 4244
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
4245
	unsigned long remainder = *nr_pages;
4246
	struct hstate *h = hstate_vma(vma);
4247
	int err = -EFAULT;
D
David Gibson 已提交
4248 4249

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
4250
		pte_t *pte;
4251
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
4252
		int absent;
A
Adam Litke 已提交
4253
		struct page *page;
D
David Gibson 已提交
4254

4255 4256 4257 4258
		/*
		 * If we have a pending SIGKILL, don't keep faulting pages and
		 * potentially allocating memory.
		 */
4259
		if (fatal_signal_pending(current)) {
4260 4261 4262 4263
			remainder = 0;
			break;
		}

A
Adam Litke 已提交
4264 4265
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
4266
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
4267
		 * first, for the page indexing below to work.
4268 4269
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
4270
		 */
4271 4272
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
				      huge_page_size(h));
4273 4274
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
4275 4276 4277 4278
		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
4279 4280 4281 4282
		 * 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
4283
		 */
H
Hugh Dickins 已提交
4284 4285
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4286 4287
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
4288 4289 4290
			remainder = 0;
			break;
		}
D
David Gibson 已提交
4291

4292 4293 4294 4295 4296 4297 4298 4299 4300 4301 4302
		/*
		 * 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)) ||
4303 4304
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
4305
			vm_fault_t ret;
4306
			unsigned int fault_flags = 0;
D
David Gibson 已提交
4307

4308 4309
			if (pte)
				spin_unlock(ptl);
4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321 4322 4323
			if (flags & FOLL_WRITE)
				fault_flags |= FAULT_FLAG_WRITE;
			if (nonblocking)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY;
			if (flags & FOLL_NOWAIT)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_RETRY_NOWAIT;
			if (flags & FOLL_TRIED) {
				VM_WARN_ON_ONCE(fault_flags &
						FAULT_FLAG_ALLOW_RETRY);
				fault_flags |= FAULT_FLAG_TRIED;
			}
			ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
			if (ret & VM_FAULT_ERROR) {
4324
				err = vm_fault_to_errno(ret, flags);
4325 4326 4327 4328
				remainder = 0;
				break;
			}
			if (ret & VM_FAULT_RETRY) {
4329 4330
				if (nonblocking &&
				    !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4331 4332 4333 4334 4335 4336 4337 4338 4339 4340 4341 4342 4343 4344
					*nonblocking = 0;
				*nr_pages = 0;
				/*
				 * VM_FAULT_RETRY must not return an
				 * error, it will return zero
				 * instead.
				 *
				 * No need to update "position" as the
				 * caller will not check it after
				 * *nr_pages is set to 0.
				 */
				return i;
			}
			continue;
A
Adam Litke 已提交
4345 4346
		}

4347
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4348
		page = pte_page(huge_ptep_get(pte));
4349 4350 4351 4352 4353 4354 4355 4356 4357 4358 4359 4360 4361

		/*
		 * Instead of doing 'try_get_page()' below in the same_page
		 * loop, just check the count once here.
		 */
		if (unlikely(page_count(page) <= 0)) {
			if (pages) {
				spin_unlock(ptl);
				remainder = 0;
				err = -ENOMEM;
				break;
			}
		}
4362
same_page:
4363
		if (pages) {
H
Hugh Dickins 已提交
4364
			pages[i] = mem_map_offset(page, pfn_offset);
4365
			get_page(pages[i]);
4366
		}
D
David Gibson 已提交
4367 4368 4369 4370 4371

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
4372
		++pfn_offset;
D
David Gibson 已提交
4373 4374
		--remainder;
		++i;
4375
		if (vaddr < vma->vm_end && remainder &&
4376
				pfn_offset < pages_per_huge_page(h)) {
4377 4378 4379 4380 4381 4382
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
4383
		spin_unlock(ptl);
D
David Gibson 已提交
4384
	}
4385
	*nr_pages = remainder;
4386 4387 4388 4389 4390
	/*
	 * setting position is actually required only if remainder is
	 * not zero but it's faster not to add a "if (remainder)"
	 * branch.
	 */
D
David Gibson 已提交
4391 4392
	*position = vaddr;

4393
	return i ? i : err;
D
David Gibson 已提交
4394
}
4395

4396 4397 4398 4399 4400 4401 4402 4403
#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

4404
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4405 4406 4407 4408 4409 4410
		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;
4411
	struct hstate *h = hstate_vma(vma);
4412
	unsigned long pages = 0;
4413
	bool shared_pmd = false;
4414
	struct mmu_notifier_range range;
4415 4416 4417

	/*
	 * In the case of shared PMDs, the area to flush could be beyond
4418
	 * start/end.  Set range.start/range.end to cover the maximum possible
4419 4420
	 * range if PMD sharing is possible.
	 */
4421 4422
	mmu_notifier_range_init(&range, mm, start, end);
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
4423 4424

	BUG_ON(address >= end);
4425
	flush_cache_range(vma, range.start, range.end);
4426

4427
	mmu_notifier_invalidate_range_start(&range);
4428
	i_mmap_lock_write(vma->vm_file->f_mapping);
4429
	for (; address < end; address += huge_page_size(h)) {
4430
		spinlock_t *ptl;
4431
		ptep = huge_pte_offset(mm, address, huge_page_size(h));
4432 4433
		if (!ptep)
			continue;
4434
		ptl = huge_pte_lock(h, mm, ptep);
4435 4436
		if (huge_pmd_unshare(mm, &address, ptep)) {
			pages++;
4437
			spin_unlock(ptl);
4438
			shared_pmd = true;
4439
			continue;
4440
		}
4441 4442 4443 4444 4445 4446 4447 4448 4449 4450 4451 4452 4453
		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);
4454 4455
				set_huge_swap_pte_at(mm, address, ptep,
						     newpte, huge_page_size(h));
4456 4457 4458 4459 4460 4461
				pages++;
			}
			spin_unlock(ptl);
			continue;
		}
		if (!huge_pte_none(pte)) {
4462 4463 4464 4465
			pte_t old_pte;

			old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
			pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
4466
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
4467
			huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
4468
			pages++;
4469
		}
4470
		spin_unlock(ptl);
4471
	}
4472
	/*
4473
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4474
	 * may have cleared our pud entry and done put_page on the page table:
4475
	 * once we release i_mmap_rwsem, another task can do the final put_page
4476 4477
	 * and that page table be reused and filled with junk.  If we actually
	 * did unshare a page of pmds, flush the range corresponding to the pud.
4478
	 */
4479
	if (shared_pmd)
4480
		flush_hugetlb_tlb_range(vma, range.start, range.end);
4481 4482
	else
		flush_hugetlb_tlb_range(vma, start, end);
4483 4484 4485 4486
	/*
	 * No need to call mmu_notifier_invalidate_range() we are downgrading
	 * page table protection not changing it to point to a new page.
	 *
4487
	 * See Documentation/vm/mmu_notifier.rst
4488
	 */
4489
	i_mmap_unlock_write(vma->vm_file->f_mapping);
4490
	mmu_notifier_invalidate_range_end(&range);
4491 4492

	return pages << h->order;
4493 4494
}

4495 4496
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
4497
					struct vm_area_struct *vma,
4498
					vm_flags_t vm_flags)
4499
{
4500
	long ret, chg;
4501
	struct hstate *h = hstate_inode(inode);
4502
	struct hugepage_subpool *spool = subpool_inode(inode);
4503
	struct resv_map *resv_map;
4504
	long gbl_reserve;
4505

4506 4507 4508 4509 4510 4511
	/* This should never happen */
	if (from > to) {
		VM_WARN(1, "%s called with a negative range\n", __func__);
		return -EINVAL;
	}

4512 4513 4514
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
4515
	 * without using reserves
4516
	 */
4517
	if (vm_flags & VM_NORESERVE)
4518 4519
		return 0;

4520 4521 4522 4523 4524 4525
	/*
	 * 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
	 */
4526
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
4527
		resv_map = inode_resv_map(inode);
4528

4529
		chg = region_chg(resv_map, from, to);
4530 4531 4532

	} else {
		resv_map = resv_map_alloc();
4533 4534 4535
		if (!resv_map)
			return -ENOMEM;

4536
		chg = to - from;
4537

4538 4539 4540 4541
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

4542 4543 4544 4545
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
4546

4547 4548 4549 4550 4551 4552 4553
	/*
	 * 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) {
4554 4555 4556
		ret = -ENOSPC;
		goto out_err;
	}
4557 4558

	/*
4559
	 * Check enough hugepages are available for the reservation.
4560
	 * Hand the pages back to the subpool if there are not
4561
	 */
4562
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
4563
	if (ret < 0) {
4564 4565
		/* put back original number of pages, chg */
		(void)hugepage_subpool_put_pages(spool, chg);
4566
		goto out_err;
K
Ken Chen 已提交
4567
	}
4568 4569 4570 4571 4572 4573 4574 4575 4576 4577 4578 4579

	/*
	 * 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
	 */
4580 4581 4582 4583 4584 4585 4586 4587 4588 4589 4590 4591 4592 4593 4594 4595 4596 4597
	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);
		}
	}
4598
	return 0;
4599
out_err:
4600
	if (!vma || vma->vm_flags & VM_MAYSHARE)
4601 4602 4603
		/* Don't call region_abort if region_chg failed */
		if (chg >= 0)
			region_abort(resv_map, from, to);
J
Joonsoo Kim 已提交
4604 4605
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
4606
	return ret;
4607 4608
}

4609 4610
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
4611
{
4612
	struct hstate *h = hstate_inode(inode);
4613
	struct resv_map *resv_map = inode_resv_map(inode);
4614
	long chg = 0;
4615
	struct hugepage_subpool *spool = subpool_inode(inode);
4616
	long gbl_reserve;
K
Ken Chen 已提交
4617

4618 4619 4620 4621 4622 4623 4624 4625 4626 4627 4628
	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
4629
	spin_lock(&inode->i_lock);
4630
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
4631 4632
	spin_unlock(&inode->i_lock);

4633 4634 4635 4636 4637 4638
	/*
	 * 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);
4639 4640

	return 0;
4641
}
4642

4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653
#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
4654 4655
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
4656 4657 4658 4659 4660 4661 4662 4663 4664 4665 4666 4667 4668

	/*
	 * 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;
}

4669
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
4670 4671 4672 4673 4674 4675 4676
{
	unsigned long base = addr & PUD_MASK;
	unsigned long end = base + PUD_SIZE;

	/*
	 * check on proper vm_flags and page table alignment
	 */
4677
	if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
4678 4679
		return true;
	return false;
4680 4681
}

4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699 4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710
/*
 * Determine if start,end range within vma could be mapped by shared pmd.
 * If yes, adjust start and end to cover range associated with possible
 * shared pmd mappings.
 */
void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
				unsigned long *start, unsigned long *end)
{
	unsigned long check_addr = *start;

	if (!(vma->vm_flags & VM_MAYSHARE))
		return;

	for (check_addr = *start; check_addr < *end; check_addr += PUD_SIZE) {
		unsigned long a_start = check_addr & PUD_MASK;
		unsigned long a_end = a_start + PUD_SIZE;

		/*
		 * If sharing is possible, adjust start/end if necessary.
		 */
		if (range_in_vma(vma, a_start, a_end)) {
			if (a_start < *start)
				*start = a_start;
			if (a_end > *end)
				*end = a_end;
		}
	}
}

4711 4712 4713 4714
/*
 * 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
4715 4716 4717 4718
 * code much cleaner. pmd allocation is essential for the shared case because
 * pud has to be populated inside the same i_mmap_rwsem section - otherwise
 * racing tasks could either miss the sharing (see huge_pte_offset) or select a
 * bad pmd for sharing.
4719 4720 4721 4722 4723 4724 4725 4726 4727 4728 4729
 */
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;
4730
	spinlock_t *ptl;
4731 4732 4733 4734

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

4735
	i_mmap_lock_write(mapping);
4736 4737 4738 4739 4740 4741
	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

		saddr = page_table_shareable(svma, vma, addr, idx);
		if (saddr) {
4742 4743
			spte = huge_pte_offset(svma->vm_mm, saddr,
					       vma_mmu_pagesize(svma));
4744 4745 4746 4747 4748 4749 4750 4751 4752 4753
			if (spte) {
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

4754
	ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
4755
	if (pud_none(*pud)) {
4756 4757
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
4758
		mm_inc_nr_pmds(mm);
4759
	} else {
4760
		put_page(virt_to_page(spte));
4761
	}
4762
	spin_unlock(ptl);
4763 4764
out:
	pte = (pte_t *)pmd_alloc(mm, pud, addr);
4765
	i_mmap_unlock_write(mapping);
4766 4767 4768 4769 4770 4771 4772 4773 4774 4775
	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.
 *
4776
 * called with page table lock held.
4777 4778 4779 4780 4781 4782 4783
 *
 * 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);
4784 4785
	p4d_t *p4d = p4d_offset(pgd, *addr);
	pud_t *pud = pud_offset(p4d, *addr);
4786 4787 4788 4789 4790 4791 4792

	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));
4793
	mm_dec_nr_pmds(mm);
4794 4795 4796
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
4797 4798 4799 4800 4801 4802
#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;
}
4803 4804 4805 4806 4807

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	return 0;
}
4808 4809 4810 4811 4812

void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
				unsigned long *start, unsigned long *end)
{
}
4813
#define want_pmd_share()	(0)
4814 4815
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

4816 4817 4818 4819 4820
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
4821
	p4d_t *p4d;
4822 4823 4824 4825
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
4826 4827 4828
	p4d = p4d_alloc(mm, pgd, addr);
	if (!p4d)
		return NULL;
4829
	pud = pud_alloc(mm, p4d, addr);
4830 4831 4832 4833 4834 4835 4836 4837 4838 4839 4840
	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);
		}
	}
4841
	BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
4842 4843 4844 4845

	return pte;
}

4846 4847 4848 4849 4850 4851 4852 4853 4854
/*
 * huge_pte_offset() - Walk the page table to resolve the hugepage
 * entry at address @addr
 *
 * Return: Pointer to page table or swap entry (PUD or PMD) for
 * address @addr, or NULL if a p*d_none() entry is encountered and the
 * size @sz doesn't match the hugepage size at this level of the page
 * table.
 */
4855 4856
pte_t *huge_pte_offset(struct mm_struct *mm,
		       unsigned long addr, unsigned long sz)
4857 4858
{
	pgd_t *pgd;
4859
	p4d_t *p4d;
4860
	pud_t *pud;
4861
	pmd_t *pmd;
4862 4863

	pgd = pgd_offset(mm, addr);
4864 4865 4866 4867 4868
	if (!pgd_present(*pgd))
		return NULL;
	p4d = p4d_offset(pgd, addr);
	if (!p4d_present(*p4d))
		return NULL;
4869

4870
	pud = pud_offset(p4d, addr);
4871
	if (sz != PUD_SIZE && pud_none(*pud))
4872
		return NULL;
4873 4874
	/* hugepage or swap? */
	if (pud_huge(*pud) || !pud_present(*pud))
4875
		return (pte_t *)pud;
4876

4877
	pmd = pmd_offset(pud, addr);
4878 4879 4880 4881 4882 4883 4884
	if (sz != PMD_SIZE && pmd_none(*pmd))
		return NULL;
	/* hugepage or swap? */
	if (pmd_huge(*pmd) || !pmd_present(*pmd))
		return (pte_t *)pmd;

	return NULL;
4885 4886
}

4887 4888 4889 4890 4891 4892 4893 4894 4895 4896 4897 4898 4899
#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);
}

4900 4901 4902 4903 4904 4905 4906 4907
struct page * __weak
follow_huge_pd(struct vm_area_struct *vma,
	       unsigned long address, hugepd_t hpd, int flags, int pdshift)
{
	WARN(1, "hugepd follow called with no support for hugepage directory format\n");
	return NULL;
}

4908
struct page * __weak
4909
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
4910
		pmd_t *pmd, int flags)
4911
{
4912 4913
	struct page *page = NULL;
	spinlock_t *ptl;
4914
	pte_t pte;
4915 4916 4917 4918 4919 4920 4921 4922 4923
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;
4924 4925
	pte = huge_ptep_get((pte_t *)pmd);
	if (pte_present(pte)) {
4926
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
4927 4928 4929
		if (flags & FOLL_GET)
			get_page(page);
	} else {
4930
		if (is_hugetlb_entry_migration(pte)) {
4931 4932 4933 4934 4935 4936 4937 4938 4939 4940 4941
			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);
4942 4943 4944
	return page;
}

4945
struct page * __weak
4946
follow_huge_pud(struct mm_struct *mm, unsigned long address,
4947
		pud_t *pud, int flags)
4948
{
4949 4950
	if (flags & FOLL_GET)
		return NULL;
4951

4952
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
4953 4954
}

4955 4956 4957 4958 4959 4960 4961 4962 4963
struct page * __weak
follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
{
	if (flags & FOLL_GET)
		return NULL;

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

4964 4965
bool isolate_huge_page(struct page *page, struct list_head *list)
{
4966 4967
	bool ret = true;

4968
	VM_BUG_ON_PAGE(!PageHead(page), page);
4969
	spin_lock(&hugetlb_lock);
4970 4971 4972 4973 4974
	if (!page_huge_active(page) || !get_page_unless_zero(page)) {
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
4975
	list_move_tail(&page->lru, list);
4976
unlock:
4977
	spin_unlock(&hugetlb_lock);
4978
	return ret;
4979 4980 4981 4982
}

void putback_active_hugepage(struct page *page)
{
4983
	VM_BUG_ON_PAGE(!PageHead(page), page);
4984
	spin_lock(&hugetlb_lock);
4985
	set_page_huge_active(page);
4986 4987 4988 4989
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}
4990 4991 4992 4993 4994 4995 4996 4997 4998 4999 5000 5001 5002 5003 5004 5005 5006 5007 5008 5009 5010 5011 5012 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022

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

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

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

		SetPageHugeTemporary(oldpage);
		ClearPageHugeTemporary(newpage);

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