hugetlb.c 156.9 KB
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// SPDX-License-Identifier: GPL-2.0-only
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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/sched/mm.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 <linux/llist.h>
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#include <linux/cma.h>
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#include <asm/page.h>
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#include <asm/pgalloc.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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#ifdef CONFIG_CMA
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static struct cma *hugetlb_cma[MAX_NUMNODES];
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#endif
static unsigned long hugetlb_cma_size __initdata;
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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 bool __initdata parsed_valid_hugepagesz = true;
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static bool __initdata parsed_default_hugepagesz;
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/*
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 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
 * free_huge_pages, and surplus_huge_pages.
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 */
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DEFINE_SPINLOCK(hugetlb_lock);
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/*
 * Serializes faults on the same logical page.  This is used to
 * prevent spurious OOMs when the hugepage pool is fully utilized.
 */
static int num_fault_mutexes;
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struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
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/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);

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

	spin_unlock(&spool->lock);

	/* If no pages are used, and no other handles to the subpool
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	 * remain, give up any reservations based on minimum size and
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	 * 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
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 * request.  Otherwise, return the number of pages by which the
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 * global pools must be adjusted (upward).  The returned value may
 * only be different than the passed value (delta) in the case where
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 * a subpool minimum size must be maintained.
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 */
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;

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

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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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/* Helper that removes a struct file_region from the resv_map cache and returns
 * it for use.
 */
static struct file_region *
get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
{
	struct file_region *nrg = NULL;

	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 = from;
	nrg->to = to;

	return nrg;
}

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static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
					      struct file_region *rg)
{
#ifdef CONFIG_CGROUP_HUGETLB
	nrg->reservation_counter = rg->reservation_counter;
	nrg->css = rg->css;
	if (rg->css)
		css_get(rg->css);
#endif
}

/* Helper that records hugetlb_cgroup uncharge info. */
static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
						struct hstate *h,
						struct resv_map *resv,
						struct file_region *nrg)
{
#ifdef CONFIG_CGROUP_HUGETLB
	if (h_cg) {
		nrg->reservation_counter =
			&h_cg->rsvd_hugepage[hstate_index(h)];
		nrg->css = &h_cg->css;
		if (!resv->pages_per_hpage)
			resv->pages_per_hpage = pages_per_huge_page(h);
		/* pages_per_hpage should be the same for all entries in
		 * a resv_map.
		 */
		VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
	} else {
		nrg->reservation_counter = NULL;
		nrg->css = NULL;
	}
#endif
}

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static bool has_same_uncharge_info(struct file_region *rg,
				   struct file_region *org)
{
#ifdef CONFIG_CGROUP_HUGETLB
	return rg && org &&
	       rg->reservation_counter == org->reservation_counter &&
	       rg->css == org->css;

#else
	return true;
#endif
}

static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
{
	struct file_region *nrg = NULL, *prg = NULL;

	prg = list_prev_entry(rg, link);
	if (&prg->link != &resv->regions && prg->to == rg->from &&
	    has_same_uncharge_info(prg, rg)) {
		prg->to = rg->to;

		list_del(&rg->link);
		kfree(rg);

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		rg = prg;
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	}

	nrg = list_next_entry(rg, link);
	if (&nrg->link != &resv->regions && nrg->from == rg->to &&
	    has_same_uncharge_info(nrg, rg)) {
		nrg->from = rg->from;

		list_del(&rg->link);
		kfree(rg);
	}
}

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/*
 * Must be called with resv->lock held.
 *
 * Calling this with regions_needed != NULL will count the number of pages
 * to be added but will not modify the linked list. And regions_needed will
 * indicate the number of file_regions needed in the cache to carry out to add
 * the regions for this range.
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 */
static long add_reservation_in_range(struct resv_map *resv, long f, long t,
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				     struct hugetlb_cgroup *h_cg,
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				     struct hstate *h, long *regions_needed)
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{
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	long add = 0;
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	struct list_head *head = &resv->regions;
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	long last_accounted_offset = f;
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	struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;

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	if (regions_needed)
		*regions_needed = 0;
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	/* In this loop, we essentially handle an entry for the range
	 * [last_accounted_offset, rg->from), at every iteration, with some
	 * bounds checking.
	 */
	list_for_each_entry_safe(rg, trg, head, link) {
		/* Skip irrelevant regions that start before our range. */
		if (rg->from < f) {
			/* If this region ends after the last accounted offset,
			 * then we need to update last_accounted_offset.
			 */
			if (rg->to > last_accounted_offset)
				last_accounted_offset = rg->to;
			continue;
		}
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		/* When we find a region that starts beyond our range, we've
		 * finished.
		 */
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		if (rg->from > t)
			break;

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		/* Add an entry for last_accounted_offset -> rg->from, and
		 * update last_accounted_offset.
		 */
		if (rg->from > last_accounted_offset) {
			add += rg->from - last_accounted_offset;
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			if (!regions_needed) {
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				nrg = get_file_region_entry_from_cache(
					resv, last_accounted_offset, rg->from);
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				record_hugetlb_cgroup_uncharge_info(h_cg, h,
								    resv, nrg);
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				list_add(&nrg->link, rg->link.prev);
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				coalesce_file_region(resv, nrg);
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			} else
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				*regions_needed += 1;
		}

		last_accounted_offset = rg->to;
	}

	/* Handle the case where our range extends beyond
	 * last_accounted_offset.
	 */
	if (last_accounted_offset < t) {
		add += t - last_accounted_offset;
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		if (!regions_needed) {
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			nrg = get_file_region_entry_from_cache(
				resv, last_accounted_offset, t);
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			record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg);
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			list_add(&nrg->link, rg->link.prev);
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			coalesce_file_region(resv, nrg);
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		} else
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			*regions_needed += 1;
	}

	VM_BUG_ON(add < 0);
	return add;
}

/* Must be called with resv->lock acquired. Will drop lock to allocate entries.
 */
static int allocate_file_region_entries(struct resv_map *resv,
					int regions_needed)
	__must_hold(&resv->lock)
{
	struct list_head allocated_regions;
	int to_allocate = 0, i = 0;
	struct file_region *trg = NULL, *rg = NULL;

	VM_BUG_ON(regions_needed < 0);

	INIT_LIST_HEAD(&allocated_regions);

	/*
	 * Check for sufficient descriptors in the cache to accommodate
	 * the number of in progress add operations plus regions_needed.
	 *
	 * This is a while loop because when we drop the lock, some other call
	 * to region_add or region_del may have consumed some region_entries,
	 * so we keep looping here until we finally have enough entries for
	 * (adds_in_progress + regions_needed).
	 */
	while (resv->region_cache_count <
	       (resv->adds_in_progress + regions_needed)) {
		to_allocate = resv->adds_in_progress + regions_needed -
			      resv->region_cache_count;

		/* At this point, we should have enough entries in the cache
		 * for all the existings adds_in_progress. We should only be
		 * needing to allocate for regions_needed.
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		 */
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		VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);

		spin_unlock(&resv->lock);
		for (i = 0; i < to_allocate; i++) {
			trg = kmalloc(sizeof(*trg), GFP_KERNEL);
			if (!trg)
				goto out_of_memory;
			list_add(&trg->link, &allocated_regions);
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		}

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		spin_lock(&resv->lock);

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		list_splice(&allocated_regions, &resv->region_cache);
		resv->region_cache_count += to_allocate;
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	}

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	return 0;
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out_of_memory:
	list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
		list_del(&rg->link);
		kfree(rg);
	}
	return -ENOMEM;
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}

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/*
 * Add the huge page range represented by [f, t) to the reserve
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 * map.  Regions will be taken from the cache to fill in this range.
 * Sufficient regions should exist in the cache due to the previous
 * call to region_chg with the same range, but in some cases the cache will not
 * have sufficient entries due to races with other code doing region_add or
 * region_del.  The extra needed entries will be allocated.
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 *
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 * regions_needed is the out value provided by a previous call to region_chg.
 *
 * Return the number of new huge pages added to the map.  This number is greater
 * than or equal to zero.  If file_region entries needed to be allocated for
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 * this operation and we were not able to allocate, it returns -ENOMEM.
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 * region_add of regions of length 1 never allocate file_regions and cannot
 * fail; region_chg will always allocate at least 1 entry and a region_add for
 * 1 page will only require at most 1 entry.
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 */
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static long region_add(struct resv_map *resv, long f, long t,
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		       long in_regions_needed, struct hstate *h,
		       struct hugetlb_cgroup *h_cg)
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{
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	long add = 0, actual_regions_needed = 0;
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	spin_lock(&resv->lock);
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retry:

	/* Count how many regions are actually needed to execute this add. */
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	add_reservation_in_range(resv, f, t, NULL, NULL,
				 &actual_regions_needed);
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	/*
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	 * Check for sufficient descriptors in the cache to accommodate
	 * this add operation. Note that actual_regions_needed may be greater
	 * than in_regions_needed, as the resv_map may have been modified since
	 * the region_chg call. In this case, we need to make sure that we
	 * allocate extra entries, such that we have enough for all the
	 * existing adds_in_progress, plus the excess needed for this
	 * operation.
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	 */
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	if (actual_regions_needed > in_regions_needed &&
	    resv->region_cache_count <
		    resv->adds_in_progress +
			    (actual_regions_needed - in_regions_needed)) {
		/* region_add operation of range 1 should never need to
		 * allocate file_region entries.
		 */
		VM_BUG_ON(t - f <= 1);
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		if (allocate_file_region_entries(
			    resv, actual_regions_needed - in_regions_needed)) {
			return -ENOMEM;
		}
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		goto retry;
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	}

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	add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
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	resv->adds_in_progress -= in_regions_needed;
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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
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 * map.  A number of new file_region structures is added to the cache as a
 * placeholder, for the subsequent region_add call to use. At least 1
 * file_region structure is added.
 *
 * out_regions_needed is the number of regions added to the
 * resv->adds_in_progress.  This value needs to be provided to a follow up call
 * to region_add or region_abort for proper accounting.
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 *
 * 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,
		       long *out_regions_needed)
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{
	long chg = 0;

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	spin_lock(&resv->lock);
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	/* Count how many hugepages in this range are NOT represented. */
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	chg = add_reservation_in_range(resv, f, t, NULL, NULL,
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				       out_regions_needed);
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	if (*out_regions_needed == 0)
		*out_regions_needed = 1;
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	if (allocate_file_region_entries(resv, *out_regions_needed))
		return -ENOMEM;
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	resv->adds_in_progress += *out_regions_needed;
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	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
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 * is called to decrement the adds_in_progress counter. regions_needed
 * is the value returned by the region_chg call, it is used to decrement
 * the adds_in_progress counter.
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 *
 * 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.
 */
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static void region_abort(struct resv_map *resv, long f, long t,
			 long regions_needed)
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{
	spin_lock(&resv->lock);
	VM_BUG_ON(!resv->region_cache_count);
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	resv->adds_in_progress -= regions_needed;
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	spin_unlock(&resv->lock);
}

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/*
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 * Delete the specified range [f, t) from the reserve map.  If the
 * t parameter is LONG_MAX, this indicates that ALL regions after f
 * should be deleted.  Locate the regions which intersect [f, t)
 * and either trim, delete or split the existing regions.
 *
 * Returns the number of huge pages deleted from the reserve map.
 * In the normal case, the return value is zero or more.  In the
 * case where a region must be split, a new region descriptor must
 * be allocated.  If the allocation fails, -ENOMEM will be returned.
 * NOTE: If the parameter t == LONG_MAX, then we will never split
 * a region and possibly return -ENOMEM.  Callers specifying
 * t == LONG_MAX do not need to check for -ENOMEM error.
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 */
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static long region_del(struct resv_map *resv, long f, long t)
606
{
607
	struct list_head *head = &resv->regions;
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	struct file_region *rg, *trg;
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	struct file_region *nrg = NULL;
	long del = 0;
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612
retry:
613
	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))
623
			continue;
624

625
		if (rg->from >= t)
626 627
			break;

628 629 630 631 632 633 634 635 636 637 638 639 640
		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--;
			}
641

642 643 644 645 646 647 648 649 650
			if (!nrg) {
				spin_unlock(&resv->lock);
				nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
				if (!nrg)
					return -ENOMEM;
				goto retry;
			}

			del += t - f;
651 652
			hugetlb_cgroup_uncharge_file_region(
				resv, rg, t - f);
653 654 655 656

			/* New entry for end of split region */
			nrg->from = t;
			nrg->to = rg->to;
657 658 659

			copy_hugetlb_cgroup_uncharge_info(nrg, rg);

660 661 662 663 664 665 666
			INIT_LIST_HEAD(&nrg->link);

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

			list_add(&nrg->link, &rg->link);
			nrg = NULL;
667
			break;
668 669 670 671
		}

		if (f <= rg->from && t >= rg->to) { /* Remove entire region */
			del += rg->to - rg->from;
672 673
			hugetlb_cgroup_uncharge_file_region(resv, rg,
							    rg->to - rg->from);
674 675 676 677 678 679
			list_del(&rg->link);
			kfree(rg);
			continue;
		}

		if (f <= rg->from) {	/* Trim beginning of region */
680 681 682
			hugetlb_cgroup_uncharge_file_region(resv, rg,
							    t - rg->from);

683 684 685
			del += t - rg->from;
			rg->from = t;
		} else {		/* Trim end of region */
686 687
			hugetlb_cgroup_uncharge_file_region(resv, rg,
							    rg->to - f);
688 689 690

			del += rg->to - f;
			rg->to = f;
691
		}
692
	}
693 694

	spin_unlock(&resv->lock);
695 696
	kfree(nrg);
	return del;
697 698
}

699 700 701 702 703 704 705 706 707
/*
 * 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.
 */
708
void hugetlb_fix_reserve_counts(struct inode *inode)
709 710 711 712 713
{
	struct hugepage_subpool *spool = subpool_inode(inode);
	long rsv_adjust;

	rsv_adjust = hugepage_subpool_get_pages(spool, 1);
714
	if (rsv_adjust) {
715 716 717 718 719 720
		struct hstate *h = hstate_inode(inode);

		hugetlb_acct_memory(h, 1);
	}
}

721 722 723 724
/*
 * Count and return the number of huge pages in the reserve map
 * that intersect with the range [f, t).
 */
725
static long region_count(struct resv_map *resv, long f, long t)
726
{
727
	struct list_head *head = &resv->regions;
728 729 730
	struct file_region *rg;
	long chg = 0;

731
	spin_lock(&resv->lock);
732 733
	/* Locate each segment we overlap with, and count that overlap. */
	list_for_each_entry(rg, head, link) {
734 735
		long seg_from;
		long seg_to;
736 737 738 739 740 741 742 743 744 745 746

		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;
	}
747
	spin_unlock(&resv->lock);
748 749 750 751

	return chg;
}

752 753 754 755
/*
 * Convert the address within this vma to the page offset within
 * the mapping, in pagecache page units; huge pages here.
 */
756 757
static pgoff_t vma_hugecache_offset(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
758
{
759 760
	return ((address - vma->vm_start) >> huge_page_shift(h)) +
			(vma->vm_pgoff >> huge_page_order(h));
761 762
}

763 764 765 766 767
pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
				     unsigned long address)
{
	return vma_hugecache_offset(hstate_vma(vma), vma, address);
}
768
EXPORT_SYMBOL_GPL(linear_hugepage_index);
769

770 771 772 773 774 775
/*
 * 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)
{
776 777 778
	if (vma->vm_ops && vma->vm_ops->pagesize)
		return vma->vm_ops->pagesize(vma);
	return PAGE_SIZE;
779
}
780
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
781

782 783 784
/*
 * 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
785 786
 * architectures where it differs, an architecture-specific 'strong'
 * version of this symbol is required.
787
 */
788
__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
789 790 791 792
{
	return vma_kernel_pagesize(vma);
}

793 794 795 796 797 798 799
/*
 * 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)
800
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
801

802 803 804 805 806 807 808 809 810
/*
 * 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.
811 812 813 814 815 816 817 818 819
 *
 * 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.
820
 */
821 822 823 824 825 826 827 828 829 830 831
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;
}

832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850
static void
resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
					  struct hugetlb_cgroup *h_cg,
					  struct hstate *h)
{
#ifdef CONFIG_CGROUP_HUGETLB
	if (!h_cg || !h) {
		resv_map->reservation_counter = NULL;
		resv_map->pages_per_hpage = 0;
		resv_map->css = NULL;
	} else {
		resv_map->reservation_counter =
			&h_cg->rsvd_hugepage[hstate_index(h)];
		resv_map->pages_per_hpage = pages_per_huge_page(h);
		resv_map->css = &h_cg->css;
	}
#endif
}

851
struct resv_map *resv_map_alloc(void)
852 853
{
	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
854 855 856 857 858
	struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);

	if (!resv_map || !rg) {
		kfree(resv_map);
		kfree(rg);
859
		return NULL;
860
	}
861 862

	kref_init(&resv_map->refs);
863
	spin_lock_init(&resv_map->lock);
864 865
	INIT_LIST_HEAD(&resv_map->regions);

866
	resv_map->adds_in_progress = 0;
867 868 869 870 871 872 873
	/*
	 * Initialize these to 0. On shared mappings, 0's here indicate these
	 * fields don't do cgroup accounting. On private mappings, these will be
	 * re-initialized to the proper values, to indicate that hugetlb cgroup
	 * reservations are to be un-charged from here.
	 */
	resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
874 875 876 877 878

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

879 880 881
	return resv_map;
}

882
void resv_map_release(struct kref *ref)
883 884
{
	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
885 886
	struct list_head *head = &resv_map->region_cache;
	struct file_region *rg, *trg;
887 888

	/* Clear out any active regions before we release the map. */
889
	region_del(resv_map, 0, LONG_MAX);
890 891 892 893 894 895 896 897 898

	/* ... 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);

899 900 901
	kfree(resv_map);
}

902 903
static inline struct resv_map *inode_resv_map(struct inode *inode)
{
904 905 906 907 908 909 910 911 912
	/*
	 * At inode evict time, i_mapping may not point to the original
	 * address space within the inode.  This original address space
	 * contains the pointer to the resv_map.  So, always use the
	 * address space embedded within the inode.
	 * The VERY common case is inode->mapping == &inode->i_data but,
	 * this may not be true for device special inodes.
	 */
	return (struct resv_map *)(&inode->i_data)->private_data;
913 914
}

915
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
916
{
917
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
918 919 920 921 922 923 924
	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 {
925 926
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
927
	}
928 929
}

930
static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
931
{
932 933
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
934

935 936
	set_vma_private_data(vma, (get_vma_private_data(vma) &
				HPAGE_RESV_MASK) | (unsigned long)map);
937 938 939 940
}

static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
{
941 942
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
943 944

	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
945 946 947 948
}

static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
{
949
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
950 951

	return (get_vma_private_data(vma) & flag) != 0;
952 953
}

954
/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
955 956
void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
957
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
958
	if (!(vma->vm_flags & VM_MAYSHARE))
959 960 961 962
		vma->vm_private_data = (void *)0;
}

/* Returns true if the VMA has associated reserve pages */
963
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
964
{
965 966 967 968 969 970 971 972 973 974 975
	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)
976
			return true;
977
		else
978
			return false;
979
	}
980 981

	/* Shared mappings always use reserves */
982 983 984 985 986
	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
E
Ethon Paul 已提交
987
		 * fallocate.  In this case, there really are no reserves to
988 989 990 991 992 993 994
		 * use.  This situation is indicated if chg != 0.
		 */
		if (chg)
			return false;
		else
			return true;
	}
995 996 997 998 999

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020
	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;
	}
1021

1022
	return false;
1023 1024
}

1025
static void enqueue_huge_page(struct hstate *h, struct page *page)
L
Linus Torvalds 已提交
1026 1027
{
	int nid = page_to_nid(page);
1028
	list_move(&page->lru, &h->hugepage_freelists[nid]);
1029 1030
	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
L
Linus Torvalds 已提交
1031 1032
}

1033
static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1034 1035
{
	struct page *page;
1036 1037 1038 1039 1040
	bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);

	list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
		if (nocma && is_migrate_cma_page(page))
			continue;
1041

1042 1043 1044 1045 1046 1047 1048 1049
		if (PageHWPoison(page))
			continue;

		list_move(&page->lru, &h->hugepage_activelist);
		set_page_refcounted(page);
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
		return page;
1050 1051
	}

1052
	return NULL;
1053 1054
}

1055 1056
static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
		nodemask_t *nmask)
1057
{
1058 1059 1060 1061
	unsigned int cpuset_mems_cookie;
	struct zonelist *zonelist;
	struct zone *zone;
	struct zoneref *z;
1062
	int node = NUMA_NO_NODE;
1063

1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079
	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);
1080 1081 1082 1083 1084

		page = dequeue_huge_page_node_exact(h, node);
		if (page)
			return page;
	}
1085 1086 1087
	if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
		goto retry_cpuset;

1088 1089 1090
	return NULL;
}

1091 1092
static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
1093 1094
				unsigned long address, int avoid_reserve,
				long chg)
L
Linus Torvalds 已提交
1095
{
1096
	struct page *page;
1097
	struct mempolicy *mpol;
1098
	gfp_t gfp_mask;
1099
	nodemask_t *nodemask;
1100
	int nid;
L
Linus Torvalds 已提交
1101

1102 1103 1104 1105 1106
	/*
	 * 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
	 */
1107
	if (!vma_has_reserves(vma, chg) &&
1108
			h->free_huge_pages - h->resv_huge_pages == 0)
1109
		goto err;
1110

1111
	/* If reserves cannot be used, ensure enough pages are in the pool */
1112
	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1113
		goto err;
1114

1115 1116
	gfp_mask = htlb_alloc_mask(h);
	nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1117 1118 1119 1120
	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
1121
	}
1122

1123
	mpol_cond_put(mpol);
L
Linus Torvalds 已提交
1124
	return page;
1125 1126 1127

err:
	return NULL;
L
Linus Torvalds 已提交
1128 1129
}

1130 1131 1132 1133 1134 1135 1136 1137 1138
/*
 * 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)
{
1139
	nid = next_node_in(nid, *nodes_allowed);
1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200
	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--)

1201
#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1202
static void destroy_compound_gigantic_page(struct page *page,
1203
					unsigned int order)
1204 1205 1206 1207 1208
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

1209
	atomic_set(compound_mapcount_ptr(page), 0);
1210 1211 1212
	if (hpage_pincount_available(page))
		atomic_set(compound_pincount_ptr(page), 0);

1213
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1214
		clear_compound_head(p);
1215 1216 1217 1218 1219 1220 1221
		set_page_refcounted(p);
	}

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

1222
static void free_gigantic_page(struct page *page, unsigned int order)
1223
{
1224 1225 1226 1227
	/*
	 * If the page isn't allocated using the cma allocator,
	 * cma_release() returns false.
	 */
1228 1229
#ifdef CONFIG_CMA
	if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1230
		return;
1231
#endif
1232

1233 1234 1235
	free_contig_range(page_to_pfn(page), 1 << order);
}

1236
#ifdef CONFIG_CONTIG_ALLOC
1237 1238
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
		int nid, nodemask_t *nodemask)
1239
{
1240
	unsigned long nr_pages = 1UL << huge_page_order(h);
1241 1242
	if (nid == NUMA_NO_NODE)
		nid = numa_mem_id();
1243

1244 1245
#ifdef CONFIG_CMA
	{
1246 1247 1248
		struct page *page;
		int node;

1249 1250 1251
		if (hugetlb_cma[nid]) {
			page = cma_alloc(hugetlb_cma[nid], nr_pages,
					huge_page_order(h), true);
1252 1253 1254
			if (page)
				return page;
		}
1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266

		if (!(gfp_mask & __GFP_THISNODE)) {
			for_each_node_mask(node, *nodemask) {
				if (node == nid || !hugetlb_cma[node])
					continue;

				page = cma_alloc(hugetlb_cma[node], nr_pages,
						huge_page_order(h), true);
				if (page)
					return page;
			}
		}
1267
	}
1268
#endif
1269

1270
	return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1271 1272 1273
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1274
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1275 1276 1277 1278 1279 1280 1281
#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 */
1282

1283
#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1284
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1285 1286 1287 1288
					int nid, nodemask_t *nodemask)
{
	return NULL;
}
1289
static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1290
static inline void destroy_compound_gigantic_page(struct page *page,
1291
						unsigned int order) { }
1292 1293
#endif

1294
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1295 1296
{
	int i;
1297

1298
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1299
		return;
1300

1301 1302 1303
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
1304 1305
		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
1306 1307
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1308
	}
1309
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1310
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1311
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1312
	set_page_refcounted(page);
1313
	if (hstate_is_gigantic(h)) {
1314 1315 1316 1317 1318
		/*
		 * Temporarily drop the hugetlb_lock, because
		 * we might block in free_gigantic_page().
		 */
		spin_unlock(&hugetlb_lock);
1319 1320
		destroy_compound_gigantic_page(page, huge_page_order(h));
		free_gigantic_page(page, huge_page_order(h));
1321
		spin_lock(&hugetlb_lock);
1322 1323 1324
	} else {
		__free_pages(page, huge_page_order(h));
	}
A
Adam Litke 已提交
1325 1326
}

1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337
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;
}

1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362
/*
 * 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]);
}

1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384
/*
 * 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;
}

1385
static void __free_huge_page(struct page *page)
1386
{
1387 1388 1389 1390
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1391
	struct hstate *h = page_hstate(page);
1392
	int nid = page_to_nid(page);
1393 1394
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1395
	bool restore_reserve;
1396

1397 1398
	VM_BUG_ON_PAGE(page_count(page), page);
	VM_BUG_ON_PAGE(page_mapcount(page), page);
1399 1400 1401

	set_page_private(page, 0);
	page->mapping = NULL;
1402
	restore_reserve = PagePrivate(page);
1403
	ClearPagePrivate(page);
1404

1405
	/*
1406 1407 1408 1409 1410 1411
	 * 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.
1412
	 */
1413 1414 1415 1416 1417 1418 1419 1420 1421 1422
	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;
	}
1423

1424
	spin_lock(&hugetlb_lock);
1425
	clear_page_huge_active(page);
1426 1427
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1428 1429
	hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
					  pages_per_huge_page(h), page);
1430 1431 1432
	if (restore_reserve)
		h->resv_huge_pages++;

1433 1434 1435 1436 1437
	if (PageHugeTemporary(page)) {
		list_del(&page->lru);
		ClearPageHugeTemporary(page);
		update_and_free_page(h, page);
	} else if (h->surplus_huge_pages_node[nid]) {
1438 1439
		/* remove the page from active list */
		list_del(&page->lru);
1440 1441 1442
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1443
	} else {
1444
		arch_clear_hugepage_flags(page);
1445
		enqueue_huge_page(h, page);
1446
	}
1447 1448 1449
	spin_unlock(&hugetlb_lock);
}

1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497
/*
 * As free_huge_page() can be called from a non-task context, we have
 * to defer the actual freeing in a workqueue to prevent potential
 * hugetlb_lock deadlock.
 *
 * free_hpage_workfn() locklessly retrieves the linked list of pages to
 * be freed and frees them one-by-one. As the page->mapping pointer is
 * going to be cleared in __free_huge_page() anyway, it is reused as the
 * llist_node structure of a lockless linked list of huge pages to be freed.
 */
static LLIST_HEAD(hpage_freelist);

static void free_hpage_workfn(struct work_struct *work)
{
	struct llist_node *node;
	struct page *page;

	node = llist_del_all(&hpage_freelist);

	while (node) {
		page = container_of((struct address_space **)node,
				     struct page, mapping);
		node = node->next;
		__free_huge_page(page);
	}
}
static DECLARE_WORK(free_hpage_work, free_hpage_workfn);

void free_huge_page(struct page *page)
{
	/*
	 * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
	 */
	if (!in_task()) {
		/*
		 * Only call schedule_work() if hpage_freelist is previously
		 * empty. Otherwise, schedule_work() had been called but the
		 * workfn hasn't retrieved the list yet.
		 */
		if (llist_add((struct llist_node *)&page->mapping,
			      &hpage_freelist))
			schedule_work(&free_hpage_work);
		return;
	}

	__free_huge_page(page);
}

1498
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1499
{
1500
	INIT_LIST_HEAD(&page->lru);
1501
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1502
	set_hugetlb_cgroup(page, NULL);
1503
	set_hugetlb_cgroup_rsvd(page, NULL);
1504
	spin_lock(&hugetlb_lock);
1505 1506
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1507 1508 1509
	spin_unlock(&hugetlb_lock);
}

1510
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1511 1512 1513 1514 1515 1516 1517
{
	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);
1518
	__ClearPageReserved(page);
1519
	__SetPageHead(page);
1520
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1521 1522 1523 1524
		/*
		 * 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
E
Ethon Paul 已提交
1525
		 * too.  Otherwise drivers using get_user_pages() to access tail
1526 1527 1528 1529 1530 1531 1532 1533
		 * 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);
1534
		set_page_count(p, 0);
1535
		set_compound_head(p, page);
1536
	}
1537
	atomic_set(compound_mapcount_ptr(page), -1);
1538 1539 1540

	if (hpage_pincount_available(page))
		atomic_set(compound_pincount_ptr(page), 0);
1541 1542
}

A
Andrew Morton 已提交
1543 1544 1545 1546 1547
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1548 1549 1550 1551 1552 1553
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1554
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1555
}
1556 1557
EXPORT_SYMBOL_GPL(PageHuge);

1558 1559 1560 1561 1562 1563 1564 1565 1566
/*
 * 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;

1567
	return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1568 1569
}

1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
/*
 * Find address_space associated with hugetlbfs page.
 * Upon entry page is locked and page 'was' mapped although mapped state
 * could change.  If necessary, use anon_vma to find vma and associated
 * address space.  The returned mapping may be stale, but it can not be
 * invalid as page lock (which is held) is required to destroy mapping.
 */
static struct address_space *_get_hugetlb_page_mapping(struct page *hpage)
{
	struct anon_vma *anon_vma;
	pgoff_t pgoff_start, pgoff_end;
	struct anon_vma_chain *avc;
	struct address_space *mapping = page_mapping(hpage);

	/* Simple file based mapping */
	if (mapping)
		return mapping;

	/*
	 * Even anonymous hugetlbfs mappings are associated with an
	 * underlying hugetlbfs file (see hugetlb_file_setup in mmap
	 * code).  Find a vma associated with the anonymous vma, and
	 * use the file pointer to get address_space.
	 */
	anon_vma = page_lock_anon_vma_read(hpage);
	if (!anon_vma)
		return mapping;  /* NULL */

	/* Use first found vma */
	pgoff_start = page_to_pgoff(hpage);
1600
	pgoff_end = pgoff_start + pages_per_huge_page(page_hstate(hpage)) - 1;
1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669
	anon_vma_interval_tree_foreach(avc, &anon_vma->rb_root,
					pgoff_start, pgoff_end) {
		struct vm_area_struct *vma = avc->vma;

		mapping = vma->vm_file->f_mapping;
		break;
	}

	anon_vma_unlock_read(anon_vma);
	return mapping;
}

/*
 * Find and lock address space (mapping) in write mode.
 *
 * Upon entry, the page is locked which allows us to find the mapping
 * even in the case of an anon page.  However, locking order dictates
 * the i_mmap_rwsem be acquired BEFORE the page lock.  This is hugetlbfs
 * specific.  So, we first try to lock the sema while still holding the
 * page lock.  If this works, great!  If not, then we need to drop the
 * page lock and then acquire i_mmap_rwsem and reacquire page lock.  Of
 * course, need to revalidate state along the way.
 */
struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
{
	struct address_space *mapping, *mapping2;

	mapping = _get_hugetlb_page_mapping(hpage);
retry:
	if (!mapping)
		return mapping;

	/*
	 * If no contention, take lock and return
	 */
	if (i_mmap_trylock_write(mapping))
		return mapping;

	/*
	 * Must drop page lock and wait on mapping sema.
	 * Note:  Once page lock is dropped, mapping could become invalid.
	 * As a hack, increase map count until we lock page again.
	 */
	atomic_inc(&hpage->_mapcount);
	unlock_page(hpage);
	i_mmap_lock_write(mapping);
	lock_page(hpage);
	atomic_add_negative(-1, &hpage->_mapcount);

	/* verify page is still mapped */
	if (!page_mapped(hpage)) {
		i_mmap_unlock_write(mapping);
		return NULL;
	}

	/*
	 * Get address space again and verify it is the same one
	 * we locked.  If not, drop lock and retry.
	 */
	mapping2 = _get_hugetlb_page_mapping(hpage);
	if (mapping2 != mapping) {
		i_mmap_unlock_write(mapping);
		mapping = mapping2;
		goto retry;
	}

	return mapping;
}

1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686
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;
}

1687
static struct page *alloc_buddy_huge_page(struct hstate *h,
1688 1689
		gfp_t gfp_mask, int nid, nodemask_t *nmask,
		nodemask_t *node_alloc_noretry)
L
Linus Torvalds 已提交
1690
{
1691
	int order = huge_page_order(h);
L
Linus Torvalds 已提交
1692
	struct page *page;
1693
	bool alloc_try_hard = true;
1694

1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706
	/*
	 * By default we always try hard to allocate the page with
	 * __GFP_RETRY_MAYFAIL flag.  However, if we are allocating pages in
	 * a loop (to adjust global huge page counts) and previous allocation
	 * failed, do not continue to try hard on the same node.  Use the
	 * node_alloc_noretry bitmap to manage this state information.
	 */
	if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
		alloc_try_hard = false;
	gfp_mask |= __GFP_COMP|__GFP_NOWARN;
	if (alloc_try_hard)
		gfp_mask |= __GFP_RETRY_MAYFAIL;
1707 1708 1709 1710 1711 1712 1713
	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);
1714

1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730
	/*
	 * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
	 * indicates an overall state change.  Clear bit so that we resume
	 * normal 'try hard' allocations.
	 */
	if (node_alloc_noretry && page && !alloc_try_hard)
		node_clear(nid, *node_alloc_noretry);

	/*
	 * If we tried hard to get a page but failed, set bit so that
	 * subsequent attempts will not try as hard until there is an
	 * overall state change.
	 */
	if (node_alloc_noretry && !page && alloc_try_hard)
		node_set(nid, *node_alloc_noretry);

1731 1732 1733
	return page;
}

1734 1735 1736 1737 1738
/*
 * 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,
1739 1740
		gfp_t gfp_mask, int nid, nodemask_t *nmask,
		nodemask_t *node_alloc_noretry)
1741 1742 1743 1744 1745 1746 1747
{
	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,
1748
				nid, nmask, node_alloc_noretry);
1749 1750 1751 1752 1753 1754 1755 1756 1757 1758
	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;
}

1759 1760 1761 1762
/*
 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
 * manner.
 */
1763 1764
static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
				nodemask_t *node_alloc_noretry)
1765 1766 1767
{
	struct page *page;
	int nr_nodes, node;
1768
	gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1769 1770

	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1771 1772
		page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
						node_alloc_noretry);
1773
		if (page)
1774 1775 1776
			break;
	}

1777 1778
	if (!page)
		return 0;
1779

1780 1781 1782
	put_page(page); /* free it into the hugepage allocator */

	return 1;
1783 1784
}

1785 1786 1787 1788 1789 1790
/*
 * 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.
 */
1791 1792
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1793
{
1794
	int nr_nodes, node;
1795 1796
	int ret = 0;

1797
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1798 1799 1800 1801
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1802 1803
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1804
			struct page *page =
1805
				list_entry(h->hugepage_freelists[node].next,
1806 1807 1808
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1809
			h->free_huge_pages_node[node]--;
1810 1811
			if (acct_surplus) {
				h->surplus_huge_pages--;
1812
				h->surplus_huge_pages_node[node]--;
1813
			}
1814 1815
			update_and_free_page(h, page);
			ret = 1;
1816
			break;
1817
		}
1818
	}
1819 1820 1821 1822

	return ret;
}

1823 1824
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
1825 1826 1827 1828 1829 1830 1831
 * nothing for in-use hugepages and non-hugepages.
 * This function returns values like below:
 *
 *  -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
 *          (allocated or reserved.)
 *       0: successfully dissolved free hugepages or the page is not a
 *          hugepage (considered as already dissolved)
1832
 */
1833
int dissolve_free_huge_page(struct page *page)
1834
{
1835
	int rc = -EBUSY;
1836

1837 1838 1839 1840
	/* Not to disrupt normal path by vainly holding hugetlb_lock */
	if (!PageHuge(page))
		return 0;

1841
	spin_lock(&hugetlb_lock);
1842 1843 1844 1845 1846 1847
	if (!PageHuge(page)) {
		rc = 0;
		goto out;
	}

	if (!page_count(page)) {
1848 1849 1850
		struct page *head = compound_head(page);
		struct hstate *h = page_hstate(head);
		int nid = page_to_nid(head);
1851
		if (h->free_huge_pages - h->resv_huge_pages == 0)
1852
			goto out;
1853 1854 1855 1856 1857 1858 1859 1860
		/*
		 * 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);
		}
1861
		list_del(&head->lru);
1862 1863
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
1864
		h->max_huge_pages--;
1865
		update_and_free_page(h, head);
1866
		rc = 0;
1867
	}
1868
out:
1869
	spin_unlock(&hugetlb_lock);
1870
	return rc;
1871 1872 1873 1874 1875
}

/*
 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 * make specified memory blocks removable from the system.
1876 1877
 * Note that this will dissolve a free gigantic hugepage completely, if any
 * part of it lies within the given range.
1878 1879
 * Also note that if dissolve_free_huge_page() returns with an error, all
 * free hugepages that were dissolved before that error are lost.
1880
 */
1881
int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1882 1883
{
	unsigned long pfn;
1884
	struct page *page;
1885
	int rc = 0;
1886

1887
	if (!hugepages_supported())
1888
		return rc;
1889

1890 1891
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
		page = pfn_to_page(pfn);
1892 1893 1894
		rc = dissolve_free_huge_page(page);
		if (rc)
			break;
1895
	}
1896 1897

	return rc;
1898 1899
}

1900 1901 1902
/*
 * Allocates a fresh surplus page from the page allocator.
 */
1903
static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1904
		int nid, nodemask_t *nmask)
1905
{
1906
	struct page *page = NULL;
1907

1908
	if (hstate_is_gigantic(h))
1909 1910
		return NULL;

1911
	spin_lock(&hugetlb_lock);
1912 1913
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
		goto out_unlock;
1914 1915
	spin_unlock(&hugetlb_lock);

1916
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1917
	if (!page)
1918
		return NULL;
1919 1920

	spin_lock(&hugetlb_lock);
1921 1922 1923 1924 1925 1926 1927 1928 1929
	/*
	 * 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);
1930
		spin_unlock(&hugetlb_lock);
1931
		put_page(page);
1932
		return NULL;
1933 1934
	} else {
		h->surplus_huge_pages++;
1935
		h->surplus_huge_pages_node[page_to_nid(page)]++;
1936
	}
1937 1938

out_unlock:
1939
	spin_unlock(&hugetlb_lock);
1940 1941 1942 1943

	return page;
}

1944
static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1945
				     int nid, nodemask_t *nmask)
1946 1947 1948 1949 1950 1951
{
	struct page *page;

	if (hstate_is_gigantic(h))
		return NULL;

1952
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964
	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;
}

1965 1966 1967
/*
 * Use the VMA's mpolicy to allocate a huge page from the buddy.
 */
D
Dave Hansen 已提交
1968
static
1969
struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1970 1971
		struct vm_area_struct *vma, unsigned long addr)
{
1972 1973 1974 1975 1976 1977 1978
	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);
1979
	page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1980 1981 1982
	mpol_cond_put(mpol);

	return page;
1983 1984
}

1985
/* page migration callback function */
1986
struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1987
		nodemask_t *nmask, gfp_t gfp_mask)
1988 1989 1990
{
	spin_lock(&hugetlb_lock);
	if (h->free_huge_pages - h->resv_huge_pages > 0) {
1991 1992 1993 1994 1995 1996
		struct page *page;

		page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
		if (page) {
			spin_unlock(&hugetlb_lock);
			return page;
1997 1998 1999 2000
		}
	}
	spin_unlock(&hugetlb_lock);

2001
	return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
2002 2003
}

2004
/* mempolicy aware migration callback */
2005 2006
struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
		unsigned long address)
2007 2008 2009 2010 2011 2012 2013 2014 2015
{
	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);
2016
	page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
2017 2018 2019 2020 2021
	mpol_cond_put(mpol);

	return page;
}

2022
/*
L
Lucas De Marchi 已提交
2023
 * Increase the hugetlb pool such that it can accommodate a reservation
2024 2025
 * of size 'delta'.
 */
2026
static int gather_surplus_pages(struct hstate *h, int delta)
2027
	__must_hold(&hugetlb_lock)
2028 2029 2030 2031 2032
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
2033
	bool alloc_ok = true;
2034

2035
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2036
	if (needed <= 0) {
2037
		h->resv_huge_pages += delta;
2038
		return 0;
2039
	}
2040 2041 2042 2043 2044 2045 2046 2047

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
2048
		page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
2049
				NUMA_NO_NODE, NULL);
2050 2051 2052 2053
		if (!page) {
			alloc_ok = false;
			break;
		}
2054
		list_add(&page->lru, &surplus_list);
2055
		cond_resched();
2056
	}
2057
	allocated += i;
2058 2059 2060 2061 2062 2063

	/*
	 * 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);
2064 2065
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
2066 2067 2068 2069 2070 2071 2072 2073 2074 2075
	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;
	}
2076 2077
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
2078
	 * needed to accommodate the reservation.  Add the appropriate number
2079
	 * of pages to the hugetlb pool and free the extras back to the buddy
2080 2081 2082
	 * 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.
2083 2084
	 */
	needed += allocated;
2085
	h->resv_huge_pages += delta;
2086
	ret = 0;
2087

2088
	/* Free the needed pages to the hugetlb pool */
2089
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2090 2091
		if ((--needed) < 0)
			break;
2092 2093 2094 2095 2096
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
2097
		VM_BUG_ON_PAGE(page_count(page), page);
2098
		enqueue_huge_page(h, page);
2099
	}
2100
free:
2101
	spin_unlock(&hugetlb_lock);
2102 2103

	/* Free unnecessary surplus pages to the buddy allocator */
2104 2105
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
2106
	spin_lock(&hugetlb_lock);
2107 2108 2109 2110 2111

	return ret;
}

/*
2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123
 * 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.
2124
 */
2125 2126
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
2127 2128 2129
{
	unsigned long nr_pages;

2130
	/* Cannot return gigantic pages currently */
2131
	if (hstate_is_gigantic(h))
2132
		goto out;
2133

2134 2135 2136 2137
	/*
	 * Part (or even all) of the reservation could have been backed
	 * by pre-allocated pages. Only free surplus pages.
	 */
2138
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2139

2140 2141
	/*
	 * We want to release as many surplus pages as possible, spread
2142 2143 2144
	 * 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.
2145
	 * free_pool_huge_page() will balance the freed pages across the
2146
	 * on-line nodes with memory and will handle the hstate accounting.
2147 2148 2149 2150
	 *
	 * 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.
2151 2152
	 */
	while (nr_pages--) {
2153 2154
		h->resv_huge_pages--;
		unused_resv_pages--;
2155
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
2156
			goto out;
2157
		cond_resched_lock(&hugetlb_lock);
2158
	}
2159 2160 2161 2162

out:
	/* Fully uncommit the reservation */
	h->resv_huge_pages -= unused_resv_pages;
2163 2164
}

2165

2166
/*
2167
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2168
 * are used by the huge page allocation routines to manage reservations.
2169 2170 2171 2172 2173 2174
 *
 * 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
2175 2176 2177
 * 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.
2178 2179 2180 2181 2182 2183
 *
 * 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.
2184 2185 2186 2187 2188
 *
 * 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.
2189
 */
2190 2191 2192
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
2193
	VMA_END_RESV,
2194
	VMA_ADD_RESV,
2195
};
2196 2197
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
2198
				enum vma_resv_mode mode)
2199
{
2200 2201
	struct resv_map *resv;
	pgoff_t idx;
2202
	long ret;
2203
	long dummy_out_regions_needed;
2204

2205 2206
	resv = vma_resv_map(vma);
	if (!resv)
2207
		return 1;
2208

2209
	idx = vma_hugecache_offset(h, vma, addr);
2210 2211
	switch (mode) {
	case VMA_NEEDS_RESV:
2212 2213 2214 2215 2216 2217
		ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
		/* We assume that vma_reservation_* routines always operate on
		 * 1 page, and that adding to resv map a 1 page entry can only
		 * ever require 1 region.
		 */
		VM_BUG_ON(dummy_out_regions_needed != 1);
2218 2219
		break;
	case VMA_COMMIT_RESV:
2220
		ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2221 2222
		/* region_add calls of range 1 should never fail. */
		VM_BUG_ON(ret < 0);
2223
		break;
2224
	case VMA_END_RESV:
2225
		region_abort(resv, idx, idx + 1, 1);
2226 2227
		ret = 0;
		break;
2228
	case VMA_ADD_RESV:
2229
		if (vma->vm_flags & VM_MAYSHARE) {
2230
			ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2231 2232 2233 2234
			/* region_add calls of range 1 should never fail. */
			VM_BUG_ON(ret < 0);
		} else {
			region_abort(resv, idx, idx + 1, 1);
2235 2236 2237
			ret = region_del(resv, idx, idx + 1);
		}
		break;
2238 2239 2240
	default:
		BUG();
	}
2241

2242
	if (vma->vm_flags & VM_MAYSHARE)
2243
		return ret;
2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262
	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;
	}
2263
	else
2264
		return ret < 0 ? ret : 0;
2265
}
2266 2267

static long vma_needs_reservation(struct hstate *h,
2268
			struct vm_area_struct *vma, unsigned long addr)
2269
{
2270
	return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2271
}
2272

2273 2274 2275
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
2276 2277 2278
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

2279
static void vma_end_reservation(struct hstate *h,
2280 2281
			struct vm_area_struct *vma, unsigned long addr)
{
2282
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2283 2284
}

2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334
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);
	}
}

2335
struct page *alloc_huge_page(struct vm_area_struct *vma,
2336
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
2337
{
2338
	struct hugepage_subpool *spool = subpool_vma(vma);
2339
	struct hstate *h = hstate_vma(vma);
2340
	struct page *page;
2341 2342
	long map_chg, map_commit;
	long gbl_chg;
2343 2344
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
2345
	bool deferred_reserve;
2346

2347
	idx = hstate_index(h);
2348
	/*
2349 2350 2351
	 * 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).
2352
	 */
2353 2354
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
2355
		return ERR_PTR(-ENOMEM);
2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366

	/*
	 * 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) {
2367
			vma_end_reservation(h, vma, addr);
2368
			return ERR_PTR(-ENOSPC);
2369
		}
L
Linus Torvalds 已提交
2370

2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382
		/*
		 * 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;
	}

2383 2384 2385 2386 2387 2388 2389 2390 2391 2392
	/* If this allocation is not consuming a reservation, charge it now.
	 */
	deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
	if (deferred_reserve) {
		ret = hugetlb_cgroup_charge_cgroup_rsvd(
			idx, pages_per_huge_page(h), &h_cg);
		if (ret)
			goto out_subpool_put;
	}

2393
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2394
	if (ret)
2395
		goto out_uncharge_cgroup_reservation;
2396

L
Linus Torvalds 已提交
2397
	spin_lock(&hugetlb_lock);
2398 2399 2400 2401 2402 2403
	/*
	 * 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);
2404
	if (!page) {
2405
		spin_unlock(&hugetlb_lock);
2406
		page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2407 2408
		if (!page)
			goto out_uncharge_cgroup;
2409 2410 2411 2412
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
2413
		spin_lock(&hugetlb_lock);
2414
		list_add(&page->lru, &h->hugepage_activelist);
2415
		/* Fall through */
K
Ken Chen 已提交
2416
	}
2417
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2418 2419 2420 2421 2422 2423 2424 2425
	/* If allocation is not consuming a reservation, also store the
	 * hugetlb_cgroup pointer on the page.
	 */
	if (deferred_reserve) {
		hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
						  h_cg, page);
	}

2426
	spin_unlock(&hugetlb_lock);
2427

2428
	set_page_private(page, (unsigned long)spool);
2429

2430 2431
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444
		/*
		 * 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);
2445 2446 2447
		if (deferred_reserve)
			hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
					pages_per_huge_page(h), page);
2448
	}
2449
	return page;
2450 2451 2452

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2453 2454 2455 2456
out_uncharge_cgroup_reservation:
	if (deferred_reserve)
		hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
						    h_cg);
2457
out_subpool_put:
2458
	if (map_chg || avoid_reserve)
2459
		hugepage_subpool_put_pages(spool, 1);
2460
	vma_end_reservation(h, vma, addr);
2461
	return ERR_PTR(-ENOSPC);
2462 2463
}

2464 2465 2466
int alloc_bootmem_huge_page(struct hstate *h)
	__attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
int __alloc_bootmem_huge_page(struct hstate *h)
2467 2468
{
	struct huge_bootmem_page *m;
2469
	int nr_nodes, node;
2470

2471
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2472 2473
		void *addr;

2474
		addr = memblock_alloc_try_nid_raw(
2475
				huge_page_size(h), huge_page_size(h),
2476
				0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2477 2478 2479 2480 2481 2482 2483
		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;
2484
			goto found;
2485 2486 2487 2488 2489
		}
	}
	return 0;

found:
2490
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2491
	/* Put them into a private list first because mem_map is not up yet */
2492
	INIT_LIST_HEAD(&m->list);
2493 2494 2495 2496 2497
	list_add(&m->list, &huge_boot_pages);
	m->hstate = h;
	return 1;
}

2498 2499
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
2500 2501 2502 2503 2504 2505 2506
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

2507 2508 2509 2510 2511 2512
/* 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) {
2513
		struct page *page = virt_to_page(m);
2514
		struct hstate *h = m->hstate;
2515

2516
		WARN_ON(page_count(page) != 1);
2517
		prep_compound_huge_page(page, h->order);
2518
		WARN_ON(PageReserved(page));
2519
		prep_new_huge_page(h, page, page_to_nid(page));
2520 2521
		put_page(page); /* free it into the hugepage allocator */

2522 2523 2524 2525 2526 2527
		/*
		 * 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.
		 */
2528
		if (hstate_is_gigantic(h))
2529
			adjust_managed_page_count(page, 1 << h->order);
2530
		cond_resched();
2531 2532 2533
	}
}

2534
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2535 2536
{
	unsigned long i;
2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555
	nodemask_t *node_alloc_noretry;

	if (!hstate_is_gigantic(h)) {
		/*
		 * Bit mask controlling how hard we retry per-node allocations.
		 * Ignore errors as lower level routines can deal with
		 * node_alloc_noretry == NULL.  If this kmalloc fails at boot
		 * time, we are likely in bigger trouble.
		 */
		node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
						GFP_KERNEL);
	} else {
		/* allocations done at boot time */
		node_alloc_noretry = NULL;
	}

	/* bit mask controlling how hard we retry per-node allocations */
	if (node_alloc_noretry)
		nodes_clear(*node_alloc_noretry);
2556

2557
	for (i = 0; i < h->max_huge_pages; ++i) {
2558
		if (hstate_is_gigantic(h)) {
2559
			if (hugetlb_cma_size) {
2560 2561 2562
				pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
				break;
			}
2563 2564
			if (!alloc_bootmem_huge_page(h))
				break;
2565
		} else if (!alloc_pool_huge_page(h,
2566 2567
					 &node_states[N_MEMORY],
					 node_alloc_noretry))
L
Linus Torvalds 已提交
2568
			break;
2569
		cond_resched();
L
Linus Torvalds 已提交
2570
	}
2571 2572 2573
	if (i < h->max_huge_pages) {
		char buf[32];

2574
		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2575 2576 2577 2578
		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;
	}
2579 2580

	kfree(node_alloc_noretry);
2581 2582 2583 2584 2585 2586 2587
}

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

	for_each_hstate(h) {
2588 2589 2590
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2591
		/* oversize hugepages were init'ed in early boot */
2592
		if (!hstate_is_gigantic(h))
2593
			hugetlb_hstate_alloc_pages(h);
2594
	}
2595
	VM_BUG_ON(minimum_order == UINT_MAX);
2596 2597 2598 2599 2600 2601 2602
}

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

	for_each_hstate(h) {
A
Andi Kleen 已提交
2603
		char buf[32];
2604 2605

		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2606
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2607
			buf, h->free_huge_pages);
2608 2609 2610
	}
}

L
Linus Torvalds 已提交
2611
#ifdef CONFIG_HIGHMEM
2612 2613
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2614
{
2615 2616
	int i;

2617
	if (hstate_is_gigantic(h))
2618 2619
		return;

2620
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2621
		struct page *page, *next;
2622 2623 2624
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2625
				return;
L
Linus Torvalds 已提交
2626 2627 2628
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2629
			update_and_free_page(h, page);
2630 2631
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2632 2633 2634 2635
		}
	}
}
#else
2636 2637
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2638 2639 2640 2641
{
}
#endif

2642 2643 2644 2645 2646
/*
 * 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.
 */
2647 2648
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2649
{
2650
	int nr_nodes, node;
2651 2652 2653

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

2654 2655 2656 2657
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2658
		}
2659 2660 2661 2662 2663
	} 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;
2664
		}
2665 2666
	}
	return 0;
2667

2668 2669 2670 2671
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2672 2673
}

2674
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2675
static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2676
			      nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2677
{
2678
	unsigned long min_count, ret;
2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689
	NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);

	/*
	 * Bit mask controlling how hard we retry per-node allocations.
	 * If we can not allocate the bit mask, do not attempt to allocate
	 * the requested huge pages.
	 */
	if (node_alloc_noretry)
		nodes_clear(*node_alloc_noretry);
	else
		return -ENOMEM;
L
Linus Torvalds 已提交
2690

2691 2692
	spin_lock(&hugetlb_lock);

2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712
	/*
	 * 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;
	}

2713 2714 2715 2716 2717 2718 2719 2720 2721 2722
	/*
	 * 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);
2723
			NODEMASK_FREE(node_alloc_noretry);
2724 2725 2726 2727
			return -EINVAL;
		}
		/* Fall through to decrease pool */
	}
2728

2729 2730 2731 2732
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2733
	 *
2734
	 * We might race with alloc_surplus_huge_page() here and be unable
2735 2736 2737 2738
	 * 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.
2739
	 */
2740
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2741
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2742 2743 2744
			break;
	}

2745
	while (count > persistent_huge_pages(h)) {
2746 2747 2748 2749 2750 2751
		/*
		 * 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);
2752 2753 2754 2755

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

2756 2757
		ret = alloc_pool_huge_page(h, nodes_allowed,
						node_alloc_noretry);
2758 2759 2760 2761
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2762 2763 2764
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2765 2766 2767 2768 2769 2770 2771 2772
	}

	/*
	 * 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.
2773 2774 2775 2776
	 *
	 * 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
2777
	 * alloc_surplus_huge_page() is checking the global counter,
2778 2779 2780
	 * 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.
2781
	 */
2782
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2783
	min_count = max(count, min_count);
2784
	try_to_free_low(h, min_count, nodes_allowed);
2785
	while (min_count < persistent_huge_pages(h)) {
2786
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2787
			break;
2788
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2789
	}
2790
	while (count < persistent_huge_pages(h)) {
2791
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2792 2793 2794
			break;
	}
out:
2795
	h->max_huge_pages = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2796
	spin_unlock(&hugetlb_lock);
2797

2798 2799
	NODEMASK_FREE(node_alloc_noretry);

2800
	return 0;
L
Linus Torvalds 已提交
2801 2802
}

2803 2804 2805 2806 2807 2808 2809 2810 2811 2812
#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];

2813 2814 2815
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2816 2817
{
	int i;
2818

2819
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2820 2821 2822
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2823
			return &hstates[i];
2824 2825 2826
		}

	return kobj_to_node_hstate(kobj, nidp);
2827 2828
}

2829
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2830 2831
					struct kobj_attribute *attr, char *buf)
{
2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842
	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);
2843
}
2844

2845 2846 2847
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2848 2849
{
	int err;
2850
	nodemask_t nodes_allowed, *n_mask;
2851

2852 2853
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
		return -EINVAL;
2854

2855 2856 2857 2858 2859
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
2860 2861 2862 2863 2864
				init_nodemask_of_mempolicy(&nodes_allowed)))
			n_mask = &node_states[N_MEMORY];
		else
			n_mask = &nodes_allowed;
	} else {
2865
		/*
2866 2867
		 * Node specific request.  count adjustment happens in
		 * set_max_huge_pages() after acquiring hugetlb_lock.
2868
		 */
2869 2870
		init_nodemask_of_node(&nodes_allowed, nid);
		n_mask = &nodes_allowed;
2871
	}
2872

2873
	err = set_max_huge_pages(h, count, nid, n_mask);
2874

2875
	return err ? err : len;
2876 2877
}

2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894
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);
}

2895 2896 2897 2898 2899 2900 2901 2902 2903
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)
{
2904
	return nr_hugepages_store_common(false, kobj, buf, len);
2905 2906 2907
}
HSTATE_ATTR(nr_hugepages);

2908 2909 2910 2911 2912 2913 2914 2915 2916 2917 2918 2919 2920 2921 2922
#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)
{
2923
	return nr_hugepages_store_common(true, kobj, buf, len);
2924 2925 2926 2927 2928
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2929 2930 2931
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2932
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2933 2934
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2935

2936 2937 2938 2939 2940
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;
2941
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2942

2943
	if (hstate_is_gigantic(h))
2944 2945
		return -EINVAL;

2946
	err = kstrtoul(buf, 10, &input);
2947
	if (err)
2948
		return err;
2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960

	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)
{
2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971
	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);
2972 2973 2974 2975 2976 2977
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2978
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2979 2980 2981 2982 2983 2984 2985
	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)
{
2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996
	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);
2997 2998 2999 3000 3001 3002 3003 3004 3005
}
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,
3006 3007 3008
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
3009 3010 3011
	NULL,
};

3012
static const struct attribute_group hstate_attr_group = {
3013 3014 3015
	.attrs = hstate_attrs,
};

J
Jeff Mahoney 已提交
3016 3017
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
3018
				    const struct attribute_group *hstate_attr_group)
3019 3020
{
	int retval;
3021
	int hi = hstate_index(h);
3022

3023 3024
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
3025 3026
		return -ENOMEM;

3027
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3028
	if (retval)
3029
		kobject_put(hstate_kobjs[hi]);
3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043

	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) {
3044 3045
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
3046
		if (err)
3047
			pr_err("HugeTLB: Unable to add hstate %s", h->name);
3048 3049 3050
	}
}

3051 3052 3053 3054
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3055 3056 3057
 * 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
3058 3059 3060 3061 3062 3063
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
3064
static struct node_hstate node_hstates[MAX_NUMNODES];
3065 3066

/*
3067
 * A subset of global hstate attributes for node devices
3068 3069 3070 3071 3072 3073 3074 3075
 */
static struct attribute *per_node_hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
	NULL,
};

3076
static const struct attribute_group per_node_hstate_attr_group = {
3077 3078 3079 3080
	.attrs = per_node_hstate_attrs,
};

/*
3081
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103
 * 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;
}

/*
3104
 * Unregister hstate attributes from a single node device.
3105 3106
 * No-op if no hstate attributes attached.
 */
3107
static void hugetlb_unregister_node(struct node *node)
3108 3109
{
	struct hstate *h;
3110
	struct node_hstate *nhs = &node_hstates[node->dev.id];
3111 3112

	if (!nhs->hugepages_kobj)
3113
		return;		/* no hstate attributes */
3114

3115 3116 3117 3118 3119
	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;
3120
		}
3121
	}
3122 3123 3124 3125 3126 3127 3128

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


/*
3129
 * Register hstate attributes for a single node device.
3130 3131
 * No-op if attributes already registered.
 */
3132
static void hugetlb_register_node(struct node *node)
3133 3134
{
	struct hstate *h;
3135
	struct node_hstate *nhs = &node_hstates[node->dev.id];
3136 3137 3138 3139 3140 3141
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3142
							&node->dev.kobj);
3143 3144 3145 3146 3147 3148 3149 3150
	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) {
3151
			pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3152
				h->name, node->dev.id);
3153 3154 3155 3156 3157 3158 3159
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
3160
 * hugetlb init time:  register hstate attributes for all registered node
3161 3162
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
3163
 */
3164
static void __init hugetlb_register_all_nodes(void)
3165 3166 3167
{
	int nid;

3168
	for_each_node_state(nid, N_MEMORY) {
3169
		struct node *node = node_devices[nid];
3170
		if (node->dev.id == nid)
3171 3172 3173 3174
			hugetlb_register_node(node);
	}

	/*
3175
	 * Let the node device driver know we're here so it can
3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194
	 * [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

3195 3196
static int __init hugetlb_init(void)
{
3197 3198
	int i;

3199 3200 3201
	if (!hugepages_supported()) {
		if (hugetlb_max_hstate || default_hstate_max_huge_pages)
			pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
3202
		return 0;
3203
	}
3204

3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232
	/*
	 * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists.  Some
	 * architectures depend on setup being done here.
	 */
	hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
	if (!parsed_default_hugepagesz) {
		/*
		 * If we did not parse a default huge page size, set
		 * default_hstate_idx to HPAGE_SIZE hstate. And, if the
		 * number of huge pages for this default size was implicitly
		 * specified, set that here as well.
		 * Note that the implicit setting will overwrite an explicit
		 * setting.  A warning will be printed in this case.
		 */
		default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
		if (default_hstate_max_huge_pages) {
			if (default_hstate.max_huge_pages) {
				char buf[32];

				string_get_size(huge_page_size(&default_hstate),
					1, STRING_UNITS_2, buf, 32);
				pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
					default_hstate.max_huge_pages, buf);
				pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
					default_hstate_max_huge_pages);
			}
			default_hstate.max_huge_pages =
				default_hstate_max_huge_pages;
3233
		}
3234
	}
3235

3236
	hugetlb_cma_check();
3237
	hugetlb_init_hstates();
3238
	gather_bootmem_prealloc();
3239 3240 3241
	report_hugepages();

	hugetlb_sysfs_init();
3242
	hugetlb_register_all_nodes();
3243
	hugetlb_cgroup_file_init();
3244

3245 3246 3247 3248 3249
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
3250
	hugetlb_fault_mutex_table =
3251 3252
		kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
			      GFP_KERNEL);
3253
	BUG_ON(!hugetlb_fault_mutex_table);
3254 3255

	for (i = 0; i < num_fault_mutexes; i++)
3256
		mutex_init(&hugetlb_fault_mutex_table[i]);
3257 3258
	return 0;
}
3259
subsys_initcall(hugetlb_init);
3260

3261 3262
/* Overwritten by architectures with more huge page sizes */
bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3263
{
3264
	return size == HPAGE_SIZE;
3265 3266
}

3267
void __init hugetlb_add_hstate(unsigned int order)
3268 3269
{
	struct hstate *h;
3270 3271
	unsigned long i;

3272 3273 3274
	if (size_to_hstate(PAGE_SIZE << order)) {
		return;
	}
3275
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3276
	BUG_ON(order == 0);
3277
	h = &hstates[hugetlb_max_hstate++];
3278 3279
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
3280 3281 3282 3283
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3284
	INIT_LIST_HEAD(&h->hugepage_activelist);
3285 3286
	h->next_nid_to_alloc = first_memory_node;
	h->next_nid_to_free = first_memory_node;
3287 3288
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
3289

3290 3291 3292
	parsed_hstate = h;
}

3293 3294 3295 3296 3297 3298 3299 3300
/*
 * hugepages command line processing
 * hugepages normally follows a valid hugepagsz or default_hugepagsz
 * specification.  If not, ignore the hugepages value.  hugepages can also
 * be the first huge page command line  option in which case it implicitly
 * specifies the number of huge pages for the default size.
 */
static int __init hugepages_setup(char *s)
3301 3302
{
	unsigned long *mhp;
3303
	static unsigned long *last_mhp;
3304

3305
	if (!parsed_valid_hugepagesz) {
3306
		pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3307
		parsed_valid_hugepagesz = true;
3308
		return 0;
3309
	}
3310

3311
	/*
3312 3313 3314 3315
	 * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
	 * yet, so this hugepages= parameter goes to the "default hstate".
	 * Otherwise, it goes with the previously parsed hugepagesz or
	 * default_hugepagesz.
3316
	 */
3317
	else if (!hugetlb_max_hstate)
3318 3319 3320 3321
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

3322
	if (mhp == last_mhp) {
3323 3324
		pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
		return 0;
3325 3326
	}

3327 3328 3329
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

3330 3331 3332 3333 3334
	/*
	 * 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.
	 */
3335
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
3336 3337 3338 3339
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

3340 3341
	return 1;
}
3342
__setup("hugepages=", hugepages_setup);
3343

3344 3345 3346 3347 3348 3349 3350
/*
 * hugepagesz command line processing
 * A specific huge page size can only be specified once with hugepagesz.
 * hugepagesz is followed by hugepages on the command line.  The global
 * variable 'parsed_valid_hugepagesz' is used to determine if prior
 * hugepagesz argument was valid.
 */
3351
static int __init hugepagesz_setup(char *s)
3352
{
3353
	unsigned long size;
3354 3355 3356
	struct hstate *h;

	parsed_valid_hugepagesz = false;
3357 3358 3359
	size = (unsigned long)memparse(s, NULL);

	if (!arch_hugetlb_valid_size(size)) {
3360
		pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3361 3362 3363
		return 0;
	}

3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386
	h = size_to_hstate(size);
	if (h) {
		/*
		 * hstate for this size already exists.  This is normally
		 * an error, but is allowed if the existing hstate is the
		 * default hstate.  More specifically, it is only allowed if
		 * the number of huge pages for the default hstate was not
		 * previously specified.
		 */
		if (!parsed_default_hugepagesz ||  h != &default_hstate ||
		    default_hstate.max_huge_pages) {
			pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
			return 0;
		}

		/*
		 * No need to call hugetlb_add_hstate() as hstate already
		 * exists.  But, do set parsed_hstate so that a following
		 * hugepages= parameter will be applied to this hstate.
		 */
		parsed_hstate = h;
		parsed_valid_hugepagesz = true;
		return 1;
3387 3388
	}

3389
	hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3390
	parsed_valid_hugepagesz = true;
3391 3392
	return 1;
}
3393 3394
__setup("hugepagesz=", hugepagesz_setup);

3395 3396 3397 3398
/*
 * default_hugepagesz command line input
 * Only one instance of default_hugepagesz allowed on command line.
 */
3399
static int __init default_hugepagesz_setup(char *s)
3400
{
3401 3402
	unsigned long size;

3403 3404 3405 3406 3407 3408
	parsed_valid_hugepagesz = false;
	if (parsed_default_hugepagesz) {
		pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
		return 0;
	}

3409 3410 3411
	size = (unsigned long)memparse(s, NULL);

	if (!arch_hugetlb_valid_size(size)) {
3412
		pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3413 3414 3415
		return 0;
	}

3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434
	hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
	parsed_valid_hugepagesz = true;
	parsed_default_hugepagesz = true;
	default_hstate_idx = hstate_index(size_to_hstate(size));

	/*
	 * The number of default huge pages (for this size) could have been
	 * specified as the first hugetlb parameter: hugepages=X.  If so,
	 * then default_hstate_max_huge_pages is set.  If the default huge
	 * page size is gigantic (>= MAX_ORDER), then the pages must be
	 * allocated here from bootmem allocator.
	 */
	if (default_hstate_max_huge_pages) {
		default_hstate.max_huge_pages = default_hstate_max_huge_pages;
		if (hstate_is_gigantic(&default_hstate))
			hugetlb_hstate_alloc_pages(&default_hstate);
		default_hstate_max_huge_pages = 0;
	}

3435 3436
	return 1;
}
3437
__setup("default_hugepagesz=", default_hugepagesz_setup);
3438

3439
static unsigned int allowed_mems_nr(struct hstate *h)
3440 3441 3442
{
	int node;
	unsigned int nr = 0;
3443 3444 3445 3446 3447
	nodemask_t *mpol_allowed;
	unsigned int *array = h->free_huge_pages_node;
	gfp_t gfp_mask = htlb_alloc_mask(h);

	mpol_allowed = policy_nodemask_current(gfp_mask);
3448

3449 3450 3451 3452 3453
	for_each_node_mask(node, cpuset_current_mems_allowed) {
		if (!mpol_allowed ||
		    (mpol_allowed && node_isset(node, *mpol_allowed)))
			nr += array[node];
	}
3454 3455 3456 3457 3458

	return nr;
}

#ifdef CONFIG_SYSCTL
3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474
static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
					  void *buffer, size_t *length,
					  loff_t *ppos, unsigned long *out)
{
	struct ctl_table dup_table;

	/*
	 * In order to avoid races with __do_proc_doulongvec_minmax(), we
	 * can duplicate the @table and alter the duplicate of it.
	 */
	dup_table = *table;
	dup_table.data = out;

	return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
}

3475 3476
static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
			 struct ctl_table *table, int write,
3477
			 void *buffer, size_t *length, loff_t *ppos)
L
Linus Torvalds 已提交
3478
{
3479
	struct hstate *h = &default_hstate;
3480
	unsigned long tmp = h->max_huge_pages;
3481
	int ret;
3482

3483
	if (!hugepages_supported())
3484
		return -EOPNOTSUPP;
3485

3486 3487
	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
					     &tmp);
3488 3489
	if (ret)
		goto out;
3490

3491 3492 3493
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
3494 3495
out:
	return ret;
L
Linus Torvalds 已提交
3496
}
3497

3498
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3499
			  void *buffer, size_t *length, loff_t *ppos)
3500 3501 3502 3503 3504 3505 3506 3507
{

	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,
3508
			  void *buffer, size_t *length, loff_t *ppos)
3509 3510 3511 3512 3513 3514
{
	return hugetlb_sysctl_handler_common(true, table, write,
							buffer, length, ppos);
}
#endif /* CONFIG_NUMA */

3515
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3516
		void *buffer, size_t *length, loff_t *ppos)
3517
{
3518
	struct hstate *h = &default_hstate;
3519
	unsigned long tmp;
3520
	int ret;
3521

3522
	if (!hugepages_supported())
3523
		return -EOPNOTSUPP;
3524

3525
	tmp = h->nr_overcommit_huge_pages;
3526

3527
	if (write && hstate_is_gigantic(h))
3528 3529
		return -EINVAL;

3530 3531
	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
					     &tmp);
3532 3533
	if (ret)
		goto out;
3534 3535 3536 3537 3538 3539

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
3540 3541
out:
	return ret;
3542 3543
}

L
Linus Torvalds 已提交
3544 3545
#endif /* CONFIG_SYSCTL */

3546
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
3547
{
3548 3549 3550
	struct hstate *h;
	unsigned long total = 0;

3551 3552
	if (!hugepages_supported())
		return;
3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573

	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
3574 3575
}

3576
int hugetlb_report_node_meminfo(char *buf, int len, int nid)
L
Linus Torvalds 已提交
3577
{
3578
	struct hstate *h = &default_hstate;
3579

3580 3581
	if (!hugepages_supported())
		return 0;
3582 3583 3584 3585 3586 3587 3588 3589

	return sysfs_emit_at(buf, len,
			     "Node %d HugePages_Total: %5u\n"
			     "Node %d HugePages_Free:  %5u\n"
			     "Node %d HugePages_Surp:  %5u\n",
			     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
3590 3591
}

3592 3593 3594 3595 3596
void hugetlb_show_meminfo(void)
{
	struct hstate *h;
	int nid;

3597 3598 3599
	if (!hugepages_supported())
		return;

3600 3601 3602 3603 3604 3605 3606 3607 3608 3609
	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));
}

3610 3611 3612 3613 3614 3615
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
3616 3617 3618
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
3619 3620 3621 3622 3623 3624
	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
3625 3626
}

3627
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643 3644 3645 3646 3647
{
	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.
3648 3649 3650 3651 3652 3653
	 *
	 * Apart from cpuset, we also have memory policy mechanism that
	 * also determines from which node the kernel will allocate memory
	 * in a NUMA system. So similar to cpuset, we also should consider
	 * the memory policy of the current task. Similar to the description
	 * above.
M
Mel Gorman 已提交
3654 3655
	 */
	if (delta > 0) {
3656
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
3657 3658
			goto out;

3659
		if (delta > allowed_mems_nr(h)) {
3660
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
3661 3662 3663 3664 3665 3666
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
3667
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
3668 3669 3670 3671 3672 3673

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

3674 3675
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
3676
	struct resv_map *resv = vma_resv_map(vma);
3677 3678 3679 3680 3681

	/*
	 * 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
3682
	 * has a reference to the reservation map it cannot disappear until
3683 3684 3685
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
3686
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3687
		kref_get(&resv->refs);
3688 3689
}

3690 3691
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
3692
	struct hstate *h = hstate_vma(vma);
3693
	struct resv_map *resv = vma_resv_map(vma);
3694
	struct hugepage_subpool *spool = subpool_vma(vma);
3695
	unsigned long reserve, start, end;
3696
	long gbl_reserve;
3697

3698 3699
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
3700

3701 3702
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
3703

3704
	reserve = (end - start) - region_count(resv, start, end);
3705
	hugetlb_cgroup_uncharge_counter(resv, start, end);
3706
	if (reserve) {
3707 3708 3709 3710 3711 3712
		/*
		 * 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);
3713
	}
3714 3715

	kref_put(&resv->refs, resv_map_release);
3716 3717
}

3718 3719 3720 3721 3722 3723 3724
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;
}

3725 3726 3727 3728 3729 3730 3731
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
3732 3733 3734 3735 3736 3737
/*
 * 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.
 */
3738
static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
L
Linus Torvalds 已提交
3739 3740
{
	BUG();
N
Nick Piggin 已提交
3741
	return 0;
L
Linus Torvalds 已提交
3742 3743
}

3744 3745 3746 3747 3748 3749 3750
/*
 * 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.
 */
3751
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
3752
	.fault = hugetlb_vm_op_fault,
3753
	.open = hugetlb_vm_op_open,
3754
	.close = hugetlb_vm_op_close,
3755
	.split = hugetlb_vm_op_split,
3756
	.pagesize = hugetlb_vm_op_pagesize,
L
Linus Torvalds 已提交
3757 3758
};

3759 3760
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
3761 3762 3763
{
	pte_t entry;

3764
	if (writable) {
3765 3766
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
3767
	} else {
3768 3769
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
3770 3771 3772
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3773
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3774 3775 3776 3777

	return entry;
}

3778 3779 3780 3781 3782
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3783
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3784
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3785
		update_mmu_cache(vma, address, ptep);
3786 3787
}

3788
bool is_hugetlb_entry_migration(pte_t pte)
3789 3790 3791 3792
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3793
		return false;
3794
	swp = pte_to_swp_entry(pte);
3795
	if (is_migration_entry(swp))
3796
		return true;
3797
	else
3798
		return false;
3799 3800
}

3801
static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
3802 3803 3804 3805
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3806
		return false;
3807
	swp = pte_to_swp_entry(pte);
3808
	if (is_hwpoison_entry(swp))
3809
		return true;
3810
	else
3811
		return false;
3812
}
3813

D
David Gibson 已提交
3814 3815 3816
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
			    struct vm_area_struct *vma)
{
3817
	pte_t *src_pte, *dst_pte, entry, dst_entry;
D
David Gibson 已提交
3818
	struct page *ptepage;
3819
	unsigned long addr;
3820
	int cow;
3821 3822
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3823
	struct address_space *mapping = vma->vm_file->f_mapping;
3824
	struct mmu_notifier_range range;
3825
	int ret = 0;
3826 3827

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3828

3829
	if (cow) {
3830
		mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3831
					vma->vm_start,
3832 3833
					vma->vm_end);
		mmu_notifier_invalidate_range_start(&range);
3834 3835 3836 3837 3838 3839 3840 3841
	} else {
		/*
		 * For shared mappings i_mmap_rwsem must be held to call
		 * huge_pte_alloc, otherwise the returned ptep could go
		 * away if part of a shared pmd and another thread calls
		 * huge_pmd_unshare.
		 */
		i_mmap_lock_read(mapping);
3842
	}
3843

3844
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3845
		spinlock_t *src_ptl, *dst_ptl;
3846
		src_pte = huge_pte_offset(src, addr, sz);
H
Hugh Dickins 已提交
3847 3848
		if (!src_pte)
			continue;
3849
		dst_pte = huge_pte_alloc(dst, addr, sz);
3850 3851 3852 3853
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3854

3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865
		/*
		 * 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))
3866 3867
			continue;

3868 3869 3870
		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);
3871
		entry = huge_ptep_get(src_pte);
3872 3873 3874 3875 3876 3877 3878
		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.
			 */
3879 3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890
			;
		} 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);
3891 3892
				set_huge_swap_pte_at(src, addr, src_pte,
						     entry, sz);
3893
			}
3894
			set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3895
		} else {
3896
			if (cow) {
3897 3898 3899 3900 3901
				/*
				 * No need to notify as we are downgrading page
				 * table protection not changing it to point
				 * to a new page.
				 *
3902
				 * See Documentation/vm/mmu_notifier.rst
3903
				 */
3904
				huge_ptep_set_wrprotect(src, addr, src_pte);
3905
			}
3906
			entry = huge_ptep_get(src_pte);
3907 3908
			ptepage = pte_page(entry);
			get_page(ptepage);
3909
			page_dup_rmap(ptepage, true);
3910
			set_huge_pte_at(dst, addr, dst_pte, entry);
3911
			hugetlb_count_add(pages_per_huge_page(h), dst);
3912
		}
3913 3914
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3915 3916
	}

3917
	if (cow)
3918
		mmu_notifier_invalidate_range_end(&range);
3919 3920
	else
		i_mmap_unlock_read(mapping);
3921 3922

	return ret;
D
David Gibson 已提交
3923 3924
}

3925 3926 3927
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
3928 3929 3930
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3931
	pte_t *ptep;
D
David Gibson 已提交
3932
	pte_t pte;
3933
	spinlock_t *ptl;
D
David Gibson 已提交
3934
	struct page *page;
3935 3936
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3937
	struct mmu_notifier_range range;
3938

D
David Gibson 已提交
3939
	WARN_ON(!is_vm_hugetlb_page(vma));
3940 3941
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3942

3943 3944 3945 3946
	/*
	 * This is a hugetlb vma, all the pte entries should point
	 * to huge page.
	 */
3947
	tlb_change_page_size(tlb, sz);
3948
	tlb_start_vma(tlb, vma);
3949 3950 3951 3952

	/*
	 * If sharing possible, alert mmu notifiers of worst case.
	 */
3953 3954
	mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
				end);
3955 3956
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
	mmu_notifier_invalidate_range_start(&range);
3957 3958
	address = start;
	for (; address < end; address += sz) {
3959
		ptep = huge_pte_offset(mm, address, sz);
A
Adam Litke 已提交
3960
		if (!ptep)
3961 3962
			continue;

3963
		ptl = huge_pte_lock(h, mm, ptep);
3964
		if (huge_pmd_unshare(mm, vma, &address, ptep)) {
3965
			spin_unlock(ptl);
3966 3967 3968 3969
			/*
			 * We just unmapped a page of PMDs by clearing a PUD.
			 * The caller's TLB flush range should cover this area.
			 */
3970 3971
			continue;
		}
3972

3973
		pte = huge_ptep_get(ptep);
3974 3975 3976 3977
		if (huge_pte_none(pte)) {
			spin_unlock(ptl);
			continue;
		}
3978 3979

		/*
3980 3981
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3982
		 */
3983
		if (unlikely(!pte_present(pte))) {
3984
			huge_pte_clear(mm, address, ptep, sz);
3985 3986
			spin_unlock(ptl);
			continue;
3987
		}
3988 3989

		page = pte_page(pte);
3990 3991 3992 3993 3994 3995
		/*
		 * 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) {
3996 3997 3998 3999
			if (page != ref_page) {
				spin_unlock(ptl);
				continue;
			}
4000 4001 4002 4003 4004 4005 4006 4007
			/*
			 * 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);
		}

4008
		pte = huge_ptep_get_and_clear(mm, address, ptep);
4009
		tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
4010
		if (huge_pte_dirty(pte))
4011
			set_page_dirty(page);
4012

4013
		hugetlb_count_sub(pages_per_huge_page(h), mm);
4014
		page_remove_rmap(page, true);
4015

4016
		spin_unlock(ptl);
4017
		tlb_remove_page_size(tlb, page, huge_page_size(h));
4018 4019 4020 4021 4022
		/*
		 * Bail out after unmapping reference page if supplied
		 */
		if (ref_page)
			break;
4023
	}
4024
	mmu_notifier_invalidate_range_end(&range);
4025
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
4026
}
D
David Gibson 已提交
4027

4028 4029 4030 4031 4032 4033 4034 4035 4036 4037 4038 4039
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
4040
	 * is to clear it before releasing the i_mmap_rwsem. This works
4041
	 * because in the context this is called, the VMA is about to be
4042
	 * destroyed and the i_mmap_rwsem is held.
4043 4044 4045 4046
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

4047
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4048
			  unsigned long end, struct page *ref_page)
4049
{
4050 4051
	struct mm_struct *mm;
	struct mmu_gather tlb;
4052 4053 4054 4055 4056 4057 4058 4059 4060 4061 4062
	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);
4063 4064 4065

	mm = vma->vm_mm;

4066
	tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end);
4067
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4068
	tlb_finish_mmu(&tlb, tlb_start, tlb_end);
4069 4070
}

4071 4072 4073 4074 4075 4076
/*
 * 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.
 */
4077 4078
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
4079
{
4080
	struct hstate *h = hstate_vma(vma);
4081 4082 4083 4084 4085 4086 4087 4088
	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.
	 */
4089
	address = address & huge_page_mask(h);
4090 4091
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
4092
	mapping = vma->vm_file->f_mapping;
4093

4094 4095 4096 4097 4098
	/*
	 * 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
	 */
4099
	i_mmap_lock_write(mapping);
4100
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4101 4102 4103 4104
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

4105 4106 4107 4108 4109 4110 4111 4112
		/*
		 * 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;

4113 4114 4115 4116 4117 4118 4119 4120
		/*
		 * 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))
4121 4122
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
4123
	}
4124
	i_mmap_unlock_write(mapping);
4125 4126
}

4127 4128
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4129 4130 4131
 * 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.
4132
 */
4133
static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4134
		       unsigned long address, pte_t *ptep,
4135
		       struct page *pagecache_page, spinlock_t *ptl)
4136
{
4137
	pte_t pte;
4138
	struct hstate *h = hstate_vma(vma);
4139
	struct page *old_page, *new_page;
4140 4141
	int outside_reserve = 0;
	vm_fault_t ret = 0;
4142
	unsigned long haddr = address & huge_page_mask(h);
4143
	struct mmu_notifier_range range;
4144

4145
	pte = huge_ptep_get(ptep);
4146 4147
	old_page = pte_page(pte);

4148
retry_avoidcopy:
4149 4150
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
4151
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4152
		page_move_anon_rmap(old_page, vma);
4153
		set_huge_ptep_writable(vma, haddr, ptep);
N
Nick Piggin 已提交
4154
		return 0;
4155 4156
	}

4157 4158 4159 4160 4161 4162 4163 4164 4165
	/*
	 * 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.
	 */
4166
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4167 4168 4169
			old_page != pagecache_page)
		outside_reserve = 1;

4170
	get_page(old_page);
4171

4172 4173 4174 4175
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
4176
	spin_unlock(ptl);
4177
	new_page = alloc_huge_page(vma, haddr, outside_reserve);
4178

4179
	if (IS_ERR(new_page)) {
4180 4181 4182 4183 4184 4185 4186 4187
		/*
		 * 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) {
4188
			put_page(old_page);
4189
			BUG_ON(huge_pte_none(pte));
4190
			unmap_ref_private(mm, vma, old_page, haddr);
4191 4192
			BUG_ON(huge_pte_none(pte));
			spin_lock(ptl);
4193
			ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4194 4195 4196 4197 4198 4199 4200 4201
			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;
4202 4203
		}

4204
		ret = vmf_error(PTR_ERR(new_page));
4205
		goto out_release_old;
4206 4207
	}

4208 4209 4210 4211
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
4212
	if (unlikely(anon_vma_prepare(vma))) {
4213 4214
		ret = VM_FAULT_OOM;
		goto out_release_all;
4215
	}
4216

4217
	copy_user_huge_page(new_page, old_page, address, vma,
A
Andrea Arcangeli 已提交
4218
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
4219
	__SetPageUptodate(new_page);
4220

4221
	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4222
				haddr + huge_page_size(h));
4223
	mmu_notifier_invalidate_range_start(&range);
4224

4225
	/*
4226
	 * Retake the page table lock to check for racing updates
4227 4228
	 * before the page tables are altered
	 */
4229
	spin_lock(ptl);
4230
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4231
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4232 4233
		ClearPagePrivate(new_page);

4234
		/* Break COW */
4235
		huge_ptep_clear_flush(vma, haddr, ptep);
4236
		mmu_notifier_invalidate_range(mm, range.start, range.end);
4237
		set_huge_pte_at(mm, haddr, ptep,
4238
				make_huge_pte(vma, new_page, 1));
4239
		page_remove_rmap(old_page, true);
4240
		hugepage_add_new_anon_rmap(new_page, vma, haddr);
4241
		set_page_huge_active(new_page);
4242 4243 4244
		/* Make the old page be freed below */
		new_page = old_page;
	}
4245
	spin_unlock(ptl);
4246
	mmu_notifier_invalidate_range_end(&range);
4247
out_release_all:
4248
	restore_reserve_on_error(h, vma, haddr, new_page);
4249
	put_page(new_page);
4250
out_release_old:
4251
	put_page(old_page);
4252

4253 4254
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
4255 4256
}

4257
/* Return the pagecache page at a given address within a VMA */
4258 4259
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
4260 4261
{
	struct address_space *mapping;
4262
	pgoff_t idx;
4263 4264

	mapping = vma->vm_file->f_mapping;
4265
	idx = vma_hugecache_offset(h, vma, address);
4266 4267 4268 4269

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
4270 4271 4272 4273 4274
/*
 * 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
4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285 4286 4287 4288 4289
			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;
}

4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300
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);

4301 4302 4303 4304 4305 4306
	/*
	 * set page dirty so that it will not be removed from cache/file
	 * by non-hugetlbfs specific code paths.
	 */
	set_page_dirty(page);

4307 4308 4309 4310 4311 4312
	spin_lock(&inode->i_lock);
	inode->i_blocks += blocks_per_huge_page(h);
	spin_unlock(&inode->i_lock);
	return 0;
}

4313 4314 4315 4316
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)
4317
{
4318
	struct hstate *h = hstate_vma(vma);
4319
	vm_fault_t ret = VM_FAULT_SIGBUS;
4320
	int anon_rmap = 0;
A
Adam Litke 已提交
4321 4322
	unsigned long size;
	struct page *page;
4323
	pte_t new_pte;
4324
	spinlock_t *ptl;
4325
	unsigned long haddr = address & huge_page_mask(h);
4326
	bool new_page = false;
A
Adam Litke 已提交
4327

4328 4329 4330
	/*
	 * 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
4331
	 * COW. Warn that such a situation has occurred as it may not be obvious
4332 4333
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4334
		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4335
			   current->pid);
4336 4337 4338
		return ret;
	}

A
Adam Litke 已提交
4339
	/*
4340 4341 4342
	 * We can not race with truncation due to holding i_mmap_rwsem.
	 * i_size is modified when holding i_mmap_rwsem, so check here
	 * once for faults beyond end of file.
A
Adam Litke 已提交
4343
	 */
4344 4345 4346 4347
	size = i_size_read(mapping->host) >> huge_page_shift(h);
	if (idx >= size)
		goto out;

4348 4349 4350
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
4351 4352 4353 4354 4355 4356 4357
		/*
		 * Check for page in userfault range
		 */
		if (userfaultfd_missing(vma)) {
			u32 hash;
			struct vm_fault vmf = {
				.vma = vma,
4358
				.address = haddr,
4359 4360 4361 4362 4363 4364 4365 4366 4367 4368 4369
				.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
				 */
			};

			/*
4370 4371 4372
			 * hugetlb_fault_mutex and i_mmap_rwsem must be
			 * dropped before handling userfault.  Reacquire
			 * after handling fault to make calling code simpler.
4373
			 */
4374
			hash = hugetlb_fault_mutex_hash(mapping, idx);
4375
			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4376
			i_mmap_unlock_read(mapping);
4377
			ret = handle_userfault(&vmf, VM_UFFD_MISSING);
4378
			i_mmap_lock_read(mapping);
4379 4380 4381 4382
			mutex_lock(&hugetlb_fault_mutex_table[hash]);
			goto out;
		}

4383
		page = alloc_huge_page(vma, haddr, 0);
4384
		if (IS_ERR(page)) {
4385 4386 4387 4388 4389 4390 4391 4392 4393 4394 4395 4396 4397 4398 4399 4400 4401 4402 4403
			/*
			 * Returning error will result in faulting task being
			 * sent SIGBUS.  The hugetlb fault mutex prevents two
			 * tasks from racing to fault in the same page which
			 * could result in false unable to allocate errors.
			 * Page migration does not take the fault mutex, but
			 * does a clear then write of pte's under page table
			 * lock.  Page fault code could race with migration,
			 * notice the clear pte and try to allocate a page
			 * here.  Before returning error, get ptl and make
			 * sure there really is no pte entry.
			 */
			ptl = huge_pte_lock(h, mm, ptep);
			if (!huge_pte_none(huge_ptep_get(ptep))) {
				ret = 0;
				spin_unlock(ptl);
				goto out;
			}
			spin_unlock(ptl);
4404
			ret = vmf_error(PTR_ERR(page));
4405 4406
			goto out;
		}
A
Andrea Arcangeli 已提交
4407
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
4408
		__SetPageUptodate(page);
4409
		new_page = true;
4410

4411
		if (vma->vm_flags & VM_MAYSHARE) {
4412
			int err = huge_add_to_page_cache(page, mapping, idx);
4413 4414 4415 4416 4417 4418
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
4419
		} else {
4420
			lock_page(page);
4421 4422 4423 4424
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
4425
			anon_rmap = 1;
4426
		}
4427
	} else {
4428 4429 4430 4431 4432 4433
		/*
		 * 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))) {
4434
			ret = VM_FAULT_HWPOISON |
4435
				VM_FAULT_SET_HINDEX(hstate_index(h));
4436 4437
			goto backout_unlocked;
		}
4438
	}
4439

4440 4441 4442 4443 4444 4445
	/*
	 * 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.
	 */
4446
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4447
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4448 4449 4450
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
4451
		/* Just decrements count, does not deallocate */
4452
		vma_end_reservation(h, vma, haddr);
4453
	}
4454

4455
	ptl = huge_pte_lock(h, mm, ptep);
N
Nick Piggin 已提交
4456
	ret = 0;
4457
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
4458 4459
		goto backout;

4460 4461
	if (anon_rmap) {
		ClearPagePrivate(page);
4462
		hugepage_add_new_anon_rmap(page, vma, haddr);
4463
	} else
4464
		page_dup_rmap(page, true);
4465 4466
	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
				&& (vma->vm_flags & VM_SHARED)));
4467
	set_huge_pte_at(mm, haddr, ptep, new_pte);
4468

4469
	hugetlb_count_add(pages_per_huge_page(h), mm);
4470
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4471
		/* Optimization, do the COW without a second fault */
4472
		ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4473 4474
	}

4475
	spin_unlock(ptl);
4476 4477 4478 4479 4480 4481 4482 4483 4484

	/*
	 * 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
4485 4486
	unlock_page(page);
out:
4487
	return ret;
A
Adam Litke 已提交
4488 4489

backout:
4490
	spin_unlock(ptl);
4491
backout_unlocked:
A
Adam Litke 已提交
4492
	unlock_page(page);
4493
	restore_reserve_on_error(h, vma, haddr, page);
A
Adam Litke 已提交
4494 4495
	put_page(page);
	goto out;
4496 4497
}

4498
#ifdef CONFIG_SMP
4499
u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4500 4501 4502 4503
{
	unsigned long key[2];
	u32 hash;

4504 4505
	key[0] = (unsigned long) mapping;
	key[1] = idx;
4506

4507
	hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4508 4509 4510 4511 4512 4513 4514 4515

	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.
 */
4516
u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4517 4518 4519 4520 4521
{
	return 0;
}
#endif

4522
vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4523
			unsigned long address, unsigned int flags)
4524
{
4525
	pte_t *ptep, entry;
4526
	spinlock_t *ptl;
4527
	vm_fault_t ret;
4528 4529
	u32 hash;
	pgoff_t idx;
4530
	struct page *page = NULL;
4531
	struct page *pagecache_page = NULL;
4532
	struct hstate *h = hstate_vma(vma);
4533
	struct address_space *mapping;
4534
	int need_wait_lock = 0;
4535
	unsigned long haddr = address & huge_page_mask(h);
4536

4537
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4538
	if (ptep) {
4539 4540 4541 4542 4543
		/*
		 * Since we hold no locks, ptep could be stale.  That is
		 * OK as we are only making decisions based on content and
		 * not actually modifying content here.
		 */
4544
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
4545
		if (unlikely(is_hugetlb_entry_migration(entry))) {
4546
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
4547 4548
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4549
			return VM_FAULT_HWPOISON_LARGE |
4550
				VM_FAULT_SET_HINDEX(hstate_index(h));
4551 4552
	}

4553 4554
	/*
	 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4555 4556 4557 4558
	 * until finished with ptep.  This serves two purposes:
	 * 1) It prevents huge_pmd_unshare from being called elsewhere
	 *    and making the ptep no longer valid.
	 * 2) It synchronizes us with i_size modifications during truncation.
4559 4560 4561 4562 4563
	 *
	 * ptep could have already be assigned via huge_pte_offset.  That
	 * is OK, as huge_pte_alloc will return the same value unless
	 * something has changed.
	 */
4564
	mapping = vma->vm_file->f_mapping;
4565 4566 4567 4568 4569 4570
	i_mmap_lock_read(mapping);
	ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
	if (!ptep) {
		i_mmap_unlock_read(mapping);
		return VM_FAULT_OOM;
	}
4571

4572 4573 4574 4575 4576
	/*
	 * 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.
	 */
4577
	idx = vma_hugecache_offset(h, vma, haddr);
4578
	hash = hugetlb_fault_mutex_hash(mapping, idx);
4579
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
4580

4581 4582
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
4583
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4584
		goto out_mutex;
4585
	}
4586

N
Nick Piggin 已提交
4587
	ret = 0;
4588

4589 4590 4591
	/*
	 * entry could be a migration/hwpoison entry at this point, so this
	 * check prevents the kernel from going below assuming that we have
E
Ethon Paul 已提交
4592 4593 4594
	 * an active hugepage in pagecache. This goto expects the 2nd page
	 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
	 * properly handle it.
4595 4596 4597 4598
	 */
	if (!pte_present(entry))
		goto out_mutex;

4599 4600 4601 4602 4603 4604 4605 4606
	/*
	 * 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.
	 */
4607
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4608
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4609
			ret = VM_FAULT_OOM;
4610
			goto out_mutex;
4611
		}
4612
		/* Just decrements count, does not deallocate */
4613
		vma_end_reservation(h, vma, haddr);
4614

4615
		if (!(vma->vm_flags & VM_MAYSHARE))
4616
			pagecache_page = hugetlbfs_pagecache_page(h,
4617
								vma, haddr);
4618 4619
	}

4620 4621 4622 4623 4624 4625
	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;

4626 4627 4628 4629 4630 4631 4632
	/*
	 * 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)
4633 4634 4635 4636
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
4637

4638
	get_page(page);
4639

4640
	if (flags & FAULT_FLAG_WRITE) {
4641
		if (!huge_pte_write(entry)) {
4642
			ret = hugetlb_cow(mm, vma, address, ptep,
4643
					  pagecache_page, ptl);
4644
			goto out_put_page;
4645
		}
4646
		entry = huge_pte_mkdirty(entry);
4647 4648
	}
	entry = pte_mkyoung(entry);
4649
	if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4650
						flags & FAULT_FLAG_WRITE))
4651
		update_mmu_cache(vma, haddr, ptep);
4652 4653 4654 4655
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
4656 4657
out_ptl:
	spin_unlock(ptl);
4658 4659 4660 4661 4662

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
4663
out_mutex:
4664
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4665
	i_mmap_unlock_read(mapping);
4666 4667 4668 4669 4670 4671 4672 4673 4674
	/*
	 * 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);
4675
	return ret;
4676 4677
}

4678 4679 4680 4681 4682 4683 4684 4685 4686 4687 4688
/*
 * 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)
{
4689 4690 4691
	struct address_space *mapping;
	pgoff_t idx;
	unsigned long size;
4692
	int vm_shared = dst_vma->vm_flags & VM_SHARED;
4693 4694 4695 4696 4697 4698 4699 4700 4701 4702 4703 4704 4705 4706
	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,
4707
						pages_per_huge_page(h), false);
4708

4709
		/* fallback to copy_from_user outside mmap_lock */
4710
		if (unlikely(ret)) {
4711
			ret = -ENOENT;
4712 4713 4714 4715 4716 4717 4718 4719 4720 4721 4722 4723 4724 4725 4726 4727
			*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);

4728 4729 4730
	mapping = dst_vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, dst_vma, dst_addr);

4731 4732 4733 4734
	/*
	 * If shared, add to page cache
	 */
	if (vm_shared) {
4735 4736 4737 4738
		size = i_size_read(mapping->host) >> huge_page_shift(h);
		ret = -EFAULT;
		if (idx >= size)
			goto out_release_nounlock;
4739

4740 4741 4742 4743 4744 4745
		/*
		 * 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.
		 */
4746 4747 4748 4749 4750
		ret = huge_add_to_page_cache(page, mapping, idx);
		if (ret)
			goto out_release_nounlock;
	}

4751 4752 4753
	ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
	spin_lock(ptl);

4754 4755 4756 4757 4758 4759 4760 4761 4762 4763 4764 4765 4766 4767
	/*
	 * 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;

4768 4769 4770 4771
	ret = -EEXIST;
	if (!huge_pte_none(huge_ptep_get(dst_pte)))
		goto out_release_unlock;

4772 4773 4774 4775 4776 4777
	if (vm_shared) {
		page_dup_rmap(page, true);
	} else {
		ClearPagePrivate(page);
		hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
	}
4778 4779 4780 4781 4782 4783 4784 4785 4786 4787 4788 4789 4790 4791 4792 4793

	_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);
4794
	set_page_huge_active(page);
4795 4796
	if (vm_shared)
		unlock_page(page);
4797 4798 4799 4800 4801
	ret = 0;
out:
	return ret;
out_release_unlock:
	spin_unlock(ptl);
4802 4803
	if (vm_shared)
		unlock_page(page);
4804
out_release_nounlock:
4805 4806 4807 4808
	put_page(page);
	goto out;
}

4809 4810 4811
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,
4812
			 long i, unsigned int flags, int *locked)
D
David Gibson 已提交
4813
{
4814 4815
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
4816
	unsigned long remainder = *nr_pages;
4817
	struct hstate *h = hstate_vma(vma);
4818
	int err = -EFAULT;
D
David Gibson 已提交
4819 4820

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
4821
		pte_t *pte;
4822
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
4823
		int absent;
A
Adam Litke 已提交
4824
		struct page *page;
D
David Gibson 已提交
4825

4826 4827 4828 4829
		/*
		 * If we have a pending SIGKILL, don't keep faulting pages and
		 * potentially allocating memory.
		 */
4830
		if (fatal_signal_pending(current)) {
4831 4832 4833 4834
			remainder = 0;
			break;
		}

A
Adam Litke 已提交
4835 4836
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
4837
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
4838
		 * first, for the page indexing below to work.
4839 4840
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
4841
		 */
4842 4843
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
				      huge_page_size(h));
4844 4845
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
4846 4847 4848 4849
		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
4850 4851 4852 4853
		 * 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
4854
		 */
H
Hugh Dickins 已提交
4855 4856
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4857 4858
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
4859 4860 4861
			remainder = 0;
			break;
		}
D
David Gibson 已提交
4862

4863 4864 4865 4866 4867 4868 4869 4870 4871 4872 4873
		/*
		 * 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)) ||
4874 4875
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
4876
			vm_fault_t ret;
4877
			unsigned int fault_flags = 0;
D
David Gibson 已提交
4878

4879 4880
			if (pte)
				spin_unlock(ptl);
4881 4882
			if (flags & FOLL_WRITE)
				fault_flags |= FAULT_FLAG_WRITE;
4883
			if (locked)
4884 4885
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_KILLABLE;
4886 4887 4888 4889
			if (flags & FOLL_NOWAIT)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_RETRY_NOWAIT;
			if (flags & FOLL_TRIED) {
4890 4891 4892 4893
				/*
				 * Note: FAULT_FLAG_ALLOW_RETRY and
				 * FAULT_FLAG_TRIED can co-exist
				 */
4894 4895 4896 4897
				fault_flags |= FAULT_FLAG_TRIED;
			}
			ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
			if (ret & VM_FAULT_ERROR) {
4898
				err = vm_fault_to_errno(ret, flags);
4899 4900 4901 4902
				remainder = 0;
				break;
			}
			if (ret & VM_FAULT_RETRY) {
4903
				if (locked &&
4904
				    !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4905
					*locked = 0;
4906 4907 4908 4909 4910 4911 4912 4913 4914 4915 4916 4917 4918
				*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
4919 4920
		}

4921
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4922
		page = pte_page(huge_ptep_get(pte));
4923

4924 4925 4926 4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937
		/*
		 * If subpage information not requested, update counters
		 * and skip the same_page loop below.
		 */
		if (!pages && !vmas && !pfn_offset &&
		    (vaddr + huge_page_size(h) < vma->vm_end) &&
		    (remainder >= pages_per_huge_page(h))) {
			vaddr += huge_page_size(h);
			remainder -= pages_per_huge_page(h);
			i += pages_per_huge_page(h);
			spin_unlock(ptl);
			continue;
		}

4938
same_page:
4939
		if (pages) {
H
Hugh Dickins 已提交
4940
			pages[i] = mem_map_offset(page, pfn_offset);
J
John Hubbard 已提交
4941 4942 4943 4944 4945 4946 4947 4948 4949 4950 4951 4952 4953 4954 4955 4956
			/*
			 * try_grab_page() should always succeed here, because:
			 * a) we hold the ptl lock, and b) we've just checked
			 * that the huge page is present in the page tables. If
			 * the huge page is present, then the tail pages must
			 * also be present. The ptl prevents the head page and
			 * tail pages from being rearranged in any way. So this
			 * page must be available at this point, unless the page
			 * refcount overflowed:
			 */
			if (WARN_ON_ONCE(!try_grab_page(pages[i], flags))) {
				spin_unlock(ptl);
				remainder = 0;
				err = -ENOMEM;
				break;
			}
4957
		}
D
David Gibson 已提交
4958 4959 4960 4961 4962

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
4963
		++pfn_offset;
D
David Gibson 已提交
4964 4965
		--remainder;
		++i;
4966
		if (vaddr < vma->vm_end && remainder &&
4967
				pfn_offset < pages_per_huge_page(h)) {
4968 4969 4970 4971 4972 4973
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
4974
		spin_unlock(ptl);
D
David Gibson 已提交
4975
	}
4976
	*nr_pages = remainder;
4977 4978 4979 4980 4981
	/*
	 * 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
4982 4983
	*position = vaddr;

4984
	return i ? i : err;
D
David Gibson 已提交
4985
}
4986

4987 4988 4989 4990 4991 4992 4993 4994
#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

4995
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4996 4997 4998 4999 5000 5001
		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;
5002
	struct hstate *h = hstate_vma(vma);
5003
	unsigned long pages = 0;
5004
	bool shared_pmd = false;
5005
	struct mmu_notifier_range range;
5006 5007 5008

	/*
	 * In the case of shared PMDs, the area to flush could be beyond
5009
	 * start/end.  Set range.start/range.end to cover the maximum possible
5010 5011
	 * range if PMD sharing is possible.
	 */
5012 5013
	mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
				0, vma, mm, start, end);
5014
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5015 5016

	BUG_ON(address >= end);
5017
	flush_cache_range(vma, range.start, range.end);
5018

5019
	mmu_notifier_invalidate_range_start(&range);
5020
	i_mmap_lock_write(vma->vm_file->f_mapping);
5021
	for (; address < end; address += huge_page_size(h)) {
5022
		spinlock_t *ptl;
5023
		ptep = huge_pte_offset(mm, address, huge_page_size(h));
5024 5025
		if (!ptep)
			continue;
5026
		ptl = huge_pte_lock(h, mm, ptep);
5027
		if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5028
			pages++;
5029
			spin_unlock(ptl);
5030
			shared_pmd = true;
5031
			continue;
5032
		}
5033 5034 5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045
		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);
5046 5047
				set_huge_swap_pte_at(mm, address, ptep,
						     newpte, huge_page_size(h));
5048 5049 5050 5051 5052 5053
				pages++;
			}
			spin_unlock(ptl);
			continue;
		}
		if (!huge_pte_none(pte)) {
5054 5055 5056 5057
			pte_t old_pte;

			old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
			pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5058
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
5059
			huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5060
			pages++;
5061
		}
5062
		spin_unlock(ptl);
5063
	}
5064
	/*
5065
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5066
	 * may have cleared our pud entry and done put_page on the page table:
5067
	 * once we release i_mmap_rwsem, another task can do the final put_page
5068 5069
	 * 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.
5070
	 */
5071
	if (shared_pmd)
5072
		flush_hugetlb_tlb_range(vma, range.start, range.end);
5073 5074
	else
		flush_hugetlb_tlb_range(vma, start, end);
5075 5076 5077 5078
	/*
	 * No need to call mmu_notifier_invalidate_range() we are downgrading
	 * page table protection not changing it to point to a new page.
	 *
5079
	 * See Documentation/vm/mmu_notifier.rst
5080
	 */
5081
	i_mmap_unlock_write(vma->vm_file->f_mapping);
5082
	mmu_notifier_invalidate_range_end(&range);
5083 5084

	return pages << h->order;
5085 5086
}

5087 5088
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
5089
					struct vm_area_struct *vma,
5090
					vm_flags_t vm_flags)
5091
{
5092
	long ret, chg, add = -1;
5093
	struct hstate *h = hstate_inode(inode);
5094
	struct hugepage_subpool *spool = subpool_inode(inode);
5095
	struct resv_map *resv_map;
5096
	struct hugetlb_cgroup *h_cg = NULL;
5097
	long gbl_reserve, regions_needed = 0;
5098

5099 5100 5101 5102 5103 5104
	/* This should never happen */
	if (from > to) {
		VM_WARN(1, "%s called with a negative range\n", __func__);
		return -EINVAL;
	}

5105 5106 5107
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
5108
	 * without using reserves
5109
	 */
5110
	if (vm_flags & VM_NORESERVE)
5111 5112
		return 0;

5113 5114 5115 5116 5117 5118
	/*
	 * 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
	 */
5119
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
5120 5121 5122 5123 5124
		/*
		 * resv_map can not be NULL as hugetlb_reserve_pages is only
		 * called for inodes for which resv_maps were created (see
		 * hugetlbfs_get_inode).
		 */
5125
		resv_map = inode_resv_map(inode);
5126

5127
		chg = region_chg(resv_map, from, to, &regions_needed);
5128 5129

	} else {
5130
		/* Private mapping. */
5131
		resv_map = resv_map_alloc();
5132 5133 5134
		if (!resv_map)
			return -ENOMEM;

5135
		chg = to - from;
5136

5137 5138 5139 5140
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

5141 5142 5143 5144
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
5145

5146 5147 5148 5149 5150 5151 5152 5153 5154 5155 5156 5157 5158 5159 5160
	ret = hugetlb_cgroup_charge_cgroup_rsvd(
		hstate_index(h), chg * pages_per_huge_page(h), &h_cg);

	if (ret < 0) {
		ret = -ENOMEM;
		goto out_err;
	}

	if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
		/* For private mappings, the hugetlb_cgroup uncharge info hangs
		 * of the resv_map.
		 */
		resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
	}

5161 5162 5163 5164 5165 5166 5167
	/*
	 * 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) {
5168
		ret = -ENOSPC;
5169
		goto out_uncharge_cgroup;
5170
	}
5171 5172

	/*
5173
	 * Check enough hugepages are available for the reservation.
5174
	 * Hand the pages back to the subpool if there are not
5175
	 */
5176
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
5177
	if (ret < 0) {
5178
		goto out_put_pages;
K
Ken Chen 已提交
5179
	}
5180 5181 5182 5183 5184 5185 5186 5187 5188 5189 5190 5191

	/*
	 * 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
	 */
5192
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
5193
		add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5194 5195 5196

		if (unlikely(add < 0)) {
			hugetlb_acct_memory(h, -gbl_reserve);
5197
			goto out_put_pages;
5198
		} else if (unlikely(chg > add)) {
5199 5200 5201 5202 5203 5204 5205 5206 5207
			/*
			 * 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;

5208 5209 5210 5211
			hugetlb_cgroup_uncharge_cgroup_rsvd(
				hstate_index(h),
				(chg - add) * pages_per_huge_page(h), h_cg);

5212 5213 5214 5215 5216
			rsv_adjust = hugepage_subpool_put_pages(spool,
								chg - add);
			hugetlb_acct_memory(h, -rsv_adjust);
		}
	}
5217
	return 0;
5218 5219 5220 5221 5222 5223
out_put_pages:
	/* put back original number of pages, chg */
	(void)hugepage_subpool_put_pages(spool, chg);
out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
					    chg * pages_per_huge_page(h), h_cg);
5224
out_err:
5225
	if (!vma || vma->vm_flags & VM_MAYSHARE)
5226 5227 5228 5229 5230
		/* Only call region_abort if the region_chg succeeded but the
		 * region_add failed or didn't run.
		 */
		if (chg >= 0 && add < 0)
			region_abort(resv_map, from, to, regions_needed);
J
Joonsoo Kim 已提交
5231 5232
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
5233
	return ret;
5234 5235
}

5236 5237
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
5238
{
5239
	struct hstate *h = hstate_inode(inode);
5240
	struct resv_map *resv_map = inode_resv_map(inode);
5241
	long chg = 0;
5242
	struct hugepage_subpool *spool = subpool_inode(inode);
5243
	long gbl_reserve;
K
Ken Chen 已提交
5244

5245 5246 5247 5248
	/*
	 * Since this routine can be called in the evict inode path for all
	 * hugetlbfs inodes, resv_map could be NULL.
	 */
5249 5250 5251 5252 5253 5254 5255 5256 5257 5258 5259
	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
5260
	spin_lock(&inode->i_lock);
5261
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
5262 5263
	spin_unlock(&inode->i_lock);

5264 5265 5266 5267 5268 5269
	/*
	 * 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);
5270 5271

	return 0;
5272
}
5273

5274 5275 5276 5277 5278 5279 5280 5281 5282 5283 5284
#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
5285 5286
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5287 5288 5289 5290 5291 5292 5293 5294 5295 5296 5297 5298 5299

	/*
	 * 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;
}

5300
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5301 5302 5303 5304 5305 5306 5307
{
	unsigned long base = addr & PUD_MASK;
	unsigned long end = base + PUD_SIZE;

	/*
	 * check on proper vm_flags and page table alignment
	 */
5308
	if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5309 5310
		return true;
	return false;
5311 5312
}

5313 5314 5315 5316 5317 5318 5319 5320
/*
 * 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)
{
5321
	unsigned long a_start, a_end;
5322 5323 5324 5325

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

5326 5327 5328
	/* Extend the range to be PUD aligned for a worst case scenario */
	a_start = ALIGN_DOWN(*start, PUD_SIZE);
	a_end = ALIGN(*end, PUD_SIZE);
5329

5330 5331 5332 5333 5334 5335
	/*
	 * Intersect the range with the vma range, since pmd sharing won't be
	 * across vma after all
	 */
	*start = max(vma->vm_start, a_start);
	*end = min(vma->vm_end, a_end);
5336 5337
}

5338 5339 5340 5341
/*
 * 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
5342 5343
 * code much cleaner.
 *
5344 5345 5346 5347 5348 5349 5350 5351 5352 5353
 * This routine must be called with i_mmap_rwsem held in at least read mode if
 * sharing is possible.  For hugetlbfs, this prevents removal of any page
 * table entries associated with the address space.  This is important as we
 * are setting up sharing based on existing page table entries (mappings).
 *
 * NOTE: This routine is only called from huge_pte_alloc.  Some callers of
 * huge_pte_alloc know that sharing is not possible and do not take
 * i_mmap_rwsem as a performance optimization.  This is handled by the
 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
 * only required for subsequent processing.
5354 5355 5356 5357 5358 5359 5360 5361 5362 5363 5364
 */
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;
5365
	spinlock_t *ptl;
5366 5367 5368 5369

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

5370
	i_mmap_assert_locked(mapping);
5371 5372 5373 5374 5375 5376
	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

		saddr = page_table_shareable(svma, vma, addr, idx);
		if (saddr) {
5377 5378
			spte = huge_pte_offset(svma->vm_mm, saddr,
					       vma_mmu_pagesize(svma));
5379 5380 5381 5382 5383 5384 5385 5386 5387 5388
			if (spte) {
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

5389
	ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5390
	if (pud_none(*pud)) {
5391 5392
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
5393
		mm_inc_nr_pmds(mm);
5394
	} else {
5395
		put_page(virt_to_page(spte));
5396
	}
5397
	spin_unlock(ptl);
5398 5399 5400 5401 5402 5403 5404 5405 5406 5407 5408 5409
out:
	pte = (pte_t *)pmd_alloc(mm, pud, addr);
	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.
 *
5410
 * Called with page table lock held and i_mmap_rwsem held in write mode.
5411 5412 5413 5414
 *
 * returns: 1 successfully unmapped a shared pte page
 *	    0 the underlying pte page is not shared, or it is the last user
 */
5415 5416
int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
					unsigned long *addr, pte_t *ptep)
5417 5418
{
	pgd_t *pgd = pgd_offset(mm, *addr);
5419 5420
	p4d_t *p4d = p4d_offset(pgd, *addr);
	pud_t *pud = pud_offset(p4d, *addr);
5421

5422
	i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5423 5424 5425 5426 5427 5428
	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));
5429
	mm_dec_nr_pmds(mm);
5430 5431 5432
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
5433 5434 5435 5436 5437 5438
#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;
}
5439

5440 5441
int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
				unsigned long *addr, pte_t *ptep)
5442 5443 5444
{
	return 0;
}
5445 5446 5447 5448 5449

void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
				unsigned long *start, unsigned long *end)
{
}
5450
#define want_pmd_share()	(0)
5451 5452
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

5453 5454 5455 5456 5457
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
5458
	p4d_t *p4d;
5459 5460 5461 5462
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
5463 5464 5465
	p4d = p4d_alloc(mm, pgd, addr);
	if (!p4d)
		return NULL;
5466
	pud = pud_alloc(mm, p4d, addr);
5467 5468 5469 5470 5471 5472 5473 5474 5475 5476 5477
	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);
		}
	}
5478
	BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5479 5480 5481 5482

	return pte;
}

5483 5484 5485 5486
/*
 * huge_pte_offset() - Walk the page table to resolve the hugepage
 * entry at address @addr
 *
5487 5488
 * Return: Pointer to page table entry (PUD or PMD) for
 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5489 5490 5491
 * size @sz doesn't match the hugepage size at this level of the page
 * table.
 */
5492 5493
pte_t *huge_pte_offset(struct mm_struct *mm,
		       unsigned long addr, unsigned long sz)
5494 5495
{
	pgd_t *pgd;
5496
	p4d_t *p4d;
5497 5498
	pud_t *pud;
	pmd_t *pmd;
5499 5500

	pgd = pgd_offset(mm, addr);
5501 5502 5503 5504 5505
	if (!pgd_present(*pgd))
		return NULL;
	p4d = p4d_offset(pgd, addr);
	if (!p4d_present(*p4d))
		return NULL;
5506

5507
	pud = pud_offset(p4d, addr);
5508 5509
	if (sz == PUD_SIZE)
		/* must be pud huge, non-present or none */
5510
		return (pte_t *)pud;
5511
	if (!pud_present(*pud))
5512
		return NULL;
5513
	/* must have a valid entry and size to go further */
5514

5515 5516 5517
	pmd = pmd_offset(pud, addr);
	/* must be pmd huge, non-present or none */
	return (pte_t *)pmd;
5518 5519
}

5520 5521 5522 5523 5524 5525 5526 5527 5528 5529 5530 5531 5532
#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);
}

5533 5534 5535 5536 5537 5538 5539 5540
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;
}

5541
struct page * __weak
5542
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5543
		pmd_t *pmd, int flags)
5544
{
5545 5546
	struct page *page = NULL;
	spinlock_t *ptl;
5547
	pte_t pte;
J
John Hubbard 已提交
5548 5549 5550 5551 5552 5553

	/* FOLL_GET and FOLL_PIN are mutually exclusive. */
	if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
			 (FOLL_PIN | FOLL_GET)))
		return NULL;

5554 5555 5556 5557 5558 5559 5560 5561 5562
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;
5563 5564
	pte = huge_ptep_get((pte_t *)pmd);
	if (pte_present(pte)) {
5565
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
J
John Hubbard 已提交
5566 5567 5568 5569 5570 5571 5572 5573 5574 5575 5576 5577
		/*
		 * try_grab_page() should always succeed here, because: a) we
		 * hold the pmd (ptl) lock, and b) we've just checked that the
		 * huge pmd (head) page is present in the page tables. The ptl
		 * prevents the head page and tail pages from being rearranged
		 * in any way. So this page must be available at this point,
		 * unless the page refcount overflowed:
		 */
		if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
			page = NULL;
			goto out;
		}
5578
	} else {
5579
		if (is_hugetlb_entry_migration(pte)) {
5580 5581 5582 5583 5584 5585 5586 5587 5588 5589 5590
			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);
5591 5592 5593
	return page;
}

5594
struct page * __weak
5595
follow_huge_pud(struct mm_struct *mm, unsigned long address,
5596
		pud_t *pud, int flags)
5597
{
J
John Hubbard 已提交
5598
	if (flags & (FOLL_GET | FOLL_PIN))
5599
		return NULL;
5600

5601
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5602 5603
}

5604 5605 5606
struct page * __weak
follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
{
J
John Hubbard 已提交
5607
	if (flags & (FOLL_GET | FOLL_PIN))
5608 5609 5610 5611 5612
		return NULL;

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

5613 5614
bool isolate_huge_page(struct page *page, struct list_head *list)
{
5615 5616
	bool ret = true;

5617
	VM_BUG_ON_PAGE(!PageHead(page), page);
5618
	spin_lock(&hugetlb_lock);
5619 5620 5621 5622 5623
	if (!page_huge_active(page) || !get_page_unless_zero(page)) {
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
5624
	list_move_tail(&page->lru, list);
5625
unlock:
5626
	spin_unlock(&hugetlb_lock);
5627
	return ret;
5628 5629 5630 5631
}

void putback_active_hugepage(struct page *page)
{
5632
	VM_BUG_ON_PAGE(!PageHead(page), page);
5633
	spin_lock(&hugetlb_lock);
5634
	set_page_huge_active(page);
5635 5636 5637 5638
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}
5639 5640 5641 5642 5643 5644 5645 5646 5647 5648 5649 5650 5651 5652 5653 5654 5655 5656 5657 5658 5659 5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671

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);
	}
}
5672 5673 5674 5675 5676 5677 5678 5679 5680 5681 5682 5683 5684 5685 5686 5687 5688 5689 5690 5691 5692 5693 5694 5695 5696 5697 5698 5699 5700 5701 5702 5703 5704 5705 5706 5707 5708 5709 5710

#ifdef CONFIG_CMA
static bool cma_reserve_called __initdata;

static int __init cmdline_parse_hugetlb_cma(char *p)
{
	hugetlb_cma_size = memparse(p, &p);
	return 0;
}

early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);

void __init hugetlb_cma_reserve(int order)
{
	unsigned long size, reserved, per_node;
	int nid;

	cma_reserve_called = true;

	if (!hugetlb_cma_size)
		return;

	if (hugetlb_cma_size < (PAGE_SIZE << order)) {
		pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
			(PAGE_SIZE << order) / SZ_1M);
		return;
	}

	/*
	 * If 3 GB area is requested on a machine with 4 numa nodes,
	 * let's allocate 1 GB on first three nodes and ignore the last one.
	 */
	per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
	pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
		hugetlb_cma_size / SZ_1M, per_node / SZ_1M);

	reserved = 0;
	for_each_node_state(nid, N_ONLINE) {
		int res;
5711
		char name[CMA_MAX_NAME];
5712 5713 5714 5715

		size = min(per_node, hugetlb_cma_size - reserved);
		size = round_up(size, PAGE_SIZE << order);

5716
		snprintf(name, sizeof(name), "hugetlb%d", nid);
5717
		res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
5718
						 0, false, name,
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						 &hugetlb_cma[nid], nid);
		if (res) {
			pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
				res, nid);
			continue;
		}

		reserved += size;
		pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
			size / SZ_1M, nid);

		if (reserved >= hugetlb_cma_size)
			break;
	}
}

void __init hugetlb_cma_check(void)
{
	if (!hugetlb_cma_size || cma_reserve_called)
		return;

	pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
}

#endif /* CONFIG_CMA */