hugetlb.c 156.2 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/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/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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static struct cma *hugetlb_cma[MAX_NUMNODES];

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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
 * the request.  Otherwise, return the number of pages by which the
 * global pools must be adjusted (upward).  The returned value may
 * only be different than the passed value (delta) in the case where
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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);
	VM_BUG_ON(!nrg);
	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);

		coalesce_file_region(resv, prg);
		return;
	}

	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);

		coalesce_file_region(resv, nrg);
		return;
	}
}

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/* Must be called with resv->lock held. Calling this with count_only == true
 * will count the number of pages to be added but will not modify the linked
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 * list. If regions_needed != NULL and count_only == true, then 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,
				     struct hstate *h, long *regions_needed,
				     bool count_only)
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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;
			if (!count_only) {
				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 if (regions_needed)
				*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;
		if (!count_only) {
			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 if (regions_needed)
			*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);

		list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
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			list_del(&rg->link);
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			list_add(&rg->link, &resv->region_cache);
			resv->region_cache_count++;
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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,
				 true);
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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, false);
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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 respresented. */
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	chg = add_reservation_in_range(resv, f, t, NULL, NULL,
				       out_regions_needed, true);
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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)
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{
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	struct list_head *head = &resv->regions;
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	struct file_region *rg, *trg;
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	struct file_region *nrg = NULL;
	long del = 0;
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retry:
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	spin_lock(&resv->lock);
616
	list_for_each_entry_safe(rg, trg, head, link) {
617 618 619 620 621 622 623 624
		/*
		 * 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))
625
			continue;
626

627
		if (rg->from >= t)
628 629
			break;

630 631 632 633 634 635 636 637 638 639 640 641 642
		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--;
			}
643

644 645 646 647 648 649 650 651 652 653 654 655 656
			if (!nrg) {
				spin_unlock(&resv->lock);
				nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
				if (!nrg)
					return -ENOMEM;
				goto retry;
			}

			del += t - f;

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

			copy_hugetlb_cgroup_uncharge_info(nrg, rg);

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

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

665 666 667
			hugetlb_cgroup_uncharge_file_region(
				resv, rg, nrg->to - nrg->from);

668 669
			list_add(&nrg->link, &rg->link);
			nrg = NULL;
670
			break;
671 672 673 674
		}

		if (f <= rg->from && t >= rg->to) { /* Remove entire region */
			del += rg->to - rg->from;
675 676
			hugetlb_cgroup_uncharge_file_region(resv, rg,
							    rg->to - rg->from);
677 678 679 680 681 682 683 684
			list_del(&rg->link);
			kfree(rg);
			continue;
		}

		if (f <= rg->from) {	/* Trim beginning of region */
			del += t - rg->from;
			rg->from = t;
685 686 687

			hugetlb_cgroup_uncharge_file_region(resv, rg,
							    t - rg->from);
688 689 690
		} else {		/* Trim end of region */
			del += rg->to - f;
			rg->to = f;
691 692 693

			hugetlb_cgroup_uncharge_file_region(resv, rg,
							    rg->to - f);
694
		}
695
	}
696 697

	spin_unlock(&resv->lock);
698 699
	kfree(nrg);
	return del;
700 701
}

702 703 704 705 706 707 708 709 710
/*
 * 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.
 */
711
void hugetlb_fix_reserve_counts(struct inode *inode)
712 713 714 715 716
{
	struct hugepage_subpool *spool = subpool_inode(inode);
	long rsv_adjust;

	rsv_adjust = hugepage_subpool_get_pages(spool, 1);
717
	if (rsv_adjust) {
718 719 720 721 722 723
		struct hstate *h = hstate_inode(inode);

		hugetlb_acct_memory(h, 1);
	}
}

724 725 726 727
/*
 * Count and return the number of huge pages in the reserve map
 * that intersect with the range [f, t).
 */
728
static long region_count(struct resv_map *resv, long f, long t)
729
{
730
	struct list_head *head = &resv->regions;
731 732 733
	struct file_region *rg;
	long chg = 0;

734
	spin_lock(&resv->lock);
735 736
	/* Locate each segment we overlap with, and count that overlap. */
	list_for_each_entry(rg, head, link) {
737 738
		long seg_from;
		long seg_to;
739 740 741 742 743 744 745 746 747 748 749

		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;
	}
750
	spin_unlock(&resv->lock);
751 752 753 754

	return chg;
}

755 756 757 758
/*
 * Convert the address within this vma to the page offset within
 * the mapping, in pagecache page units; huge pages here.
 */
759 760
static pgoff_t vma_hugecache_offset(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
761
{
762 763
	return ((address - vma->vm_start) >> huge_page_shift(h)) +
			(vma->vm_pgoff >> huge_page_order(h));
764 765
}

766 767 768 769 770
pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
				     unsigned long address)
{
	return vma_hugecache_offset(hstate_vma(vma), vma, address);
}
771
EXPORT_SYMBOL_GPL(linear_hugepage_index);
772

773 774 775 776 777 778
/*
 * 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)
{
779 780 781
	if (vma->vm_ops && vma->vm_ops->pagesize)
		return vma->vm_ops->pagesize(vma);
	return PAGE_SIZE;
782
}
783
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
784

785 786 787
/*
 * 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
788 789
 * architectures where it differs, an architecture-specific 'strong'
 * version of this symbol is required.
790
 */
791
__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
792 793 794 795
{
	return vma_kernel_pagesize(vma);
}

796 797 798 799 800 801 802
/*
 * 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)
803
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
804

805 806 807 808 809 810 811 812 813
/*
 * 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.
814 815 816 817 818 819 820 821 822
 *
 * 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.
823
 */
824 825 826 827 828 829 830 831 832 833 834
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;
}

835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853
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
}

854
struct resv_map *resv_map_alloc(void)
855 856
{
	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
857 858 859 860 861
	struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);

	if (!resv_map || !rg) {
		kfree(resv_map);
		kfree(rg);
862
		return NULL;
863
	}
864 865

	kref_init(&resv_map->refs);
866
	spin_lock_init(&resv_map->lock);
867 868
	INIT_LIST_HEAD(&resv_map->regions);

869
	resv_map->adds_in_progress = 0;
870 871 872 873 874 875 876
	/*
	 * 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);
877 878 879 880 881

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

882 883 884
	return resv_map;
}

885
void resv_map_release(struct kref *ref)
886 887
{
	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
888 889
	struct list_head *head = &resv_map->region_cache;
	struct file_region *rg, *trg;
890 891

	/* Clear out any active regions before we release the map. */
892
	region_del(resv_map, 0, LONG_MAX);
893 894 895 896 897 898 899 900 901

	/* ... 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);

902 903 904
	kfree(resv_map);
}

905 906
static inline struct resv_map *inode_resv_map(struct inode *inode)
{
907 908 909 910 911 912 913 914 915
	/*
	 * 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;
916 917
}

918
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
919
{
920
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
921 922 923 924 925 926 927
	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 {
928 929
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
930
	}
931 932
}

933
static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
934
{
935 936
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
937

938 939
	set_vma_private_data(vma, (get_vma_private_data(vma) &
				HPAGE_RESV_MASK) | (unsigned long)map);
940 941 942 943
}

static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
{
944 945
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
946 947

	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
948 949 950 951
}

static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
{
952
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
953 954

	return (get_vma_private_data(vma) & flag) != 0;
955 956
}

957
/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
958 959
void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
960
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
961
	if (!(vma->vm_flags & VM_MAYSHARE))
962 963 964 965
		vma->vm_private_data = (void *)0;
}

/* Returns true if the VMA has associated reserve pages */
966
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
967
{
968 969 970 971 972 973 974 975 976 977 978
	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)
979
			return true;
980
		else
981
			return false;
982
	}
983 984

	/* Shared mappings always use reserves */
985 986 987 988 989
	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
990
		 * fallocate.  In this case, there really are no reserves to
991 992 993 994 995 996 997
		 * use.  This situation is indicated if chg != 0.
		 */
		if (chg)
			return false;
		else
			return true;
	}
998 999 1000 1001 1002

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
	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;
	}
1024

1025
	return false;
1026 1027
}

1028
static void enqueue_huge_page(struct hstate *h, struct page *page)
L
Linus Torvalds 已提交
1029 1030
{
	int nid = page_to_nid(page);
1031
	list_move(&page->lru, &h->hugepage_freelists[nid]);
1032 1033
	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
L
Linus Torvalds 已提交
1034 1035
}

1036
static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1037 1038 1039
{
	struct page *page;

1040
	list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
1041
		if (!PageHWPoison(page))
1042 1043 1044 1045 1046 1047
			break;
	/*
	 * if 'non-isolated free hugepage' not found on the list,
	 * the allocation fails.
	 */
	if (&h->hugepage_freelists[nid] == &page->lru)
1048
		return NULL;
1049
	list_move(&page->lru, &h->hugepage_activelist);
1050
	set_page_refcounted(page);
1051 1052 1053 1054 1055
	h->free_huge_pages--;
	h->free_huge_pages_node[nid]--;
	return page;
}

1056 1057
static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
		nodemask_t *nmask)
1058
{
1059 1060 1061 1062
	unsigned int cpuset_mems_cookie;
	struct zonelist *zonelist;
	struct zone *zone;
	struct zoneref *z;
1063
	int node = NUMA_NO_NODE;
1064

1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
	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);
1081 1082 1083 1084 1085

		page = dequeue_huge_page_node_exact(h, node);
		if (page)
			return page;
	}
1086 1087 1088
	if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
		goto retry_cpuset;

1089 1090 1091
	return NULL;
}

1092 1093 1094
/* Movability of hugepages depends on migration support. */
static inline gfp_t htlb_alloc_mask(struct hstate *h)
{
1095
	if (hugepage_movable_supported(h))
1096 1097 1098 1099 1100
		return GFP_HIGHUSER_MOVABLE;
	else
		return GFP_HIGHUSER;
}

1101 1102
static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
1103 1104
				unsigned long address, int avoid_reserve,
				long chg)
L
Linus Torvalds 已提交
1105
{
1106
	struct page *page;
1107
	struct mempolicy *mpol;
1108
	gfp_t gfp_mask;
1109
	nodemask_t *nodemask;
1110
	int nid;
L
Linus Torvalds 已提交
1111

1112 1113 1114 1115 1116
	/*
	 * 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
	 */
1117
	if (!vma_has_reserves(vma, chg) &&
1118
			h->free_huge_pages - h->resv_huge_pages == 0)
1119
		goto err;
1120

1121
	/* If reserves cannot be used, ensure enough pages are in the pool */
1122
	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1123
		goto err;
1124

1125 1126
	gfp_mask = htlb_alloc_mask(h);
	nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1127 1128 1129 1130
	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
1131
	}
1132

1133
	mpol_cond_put(mpol);
L
Linus Torvalds 已提交
1134
	return page;
1135 1136 1137

err:
	return NULL;
L
Linus Torvalds 已提交
1138 1139
}

1140 1141 1142 1143 1144 1145 1146 1147 1148
/*
 * 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)
{
1149
	nid = next_node_in(nid, *nodes_allowed);
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 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210
	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--)

1211
#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1212
static void destroy_compound_gigantic_page(struct page *page,
1213
					unsigned int order)
1214 1215 1216 1217 1218
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

1219
	atomic_set(compound_mapcount_ptr(page), 0);
1220 1221 1222
	if (hpage_pincount_available(page))
		atomic_set(compound_pincount_ptr(page), 0);

1223
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1224
		clear_compound_head(p);
1225 1226 1227 1228 1229 1230 1231
		set_page_refcounted(p);
	}

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

1232
static void free_gigantic_page(struct page *page, unsigned int order)
1233
{
1234 1235 1236 1237 1238 1239 1240 1241
	/*
	 * If the page isn't allocated using the cma allocator,
	 * cma_release() returns false.
	 */
	if (IS_ENABLED(CONFIG_CMA) &&
	    cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
		return;

1242 1243 1244
	free_contig_range(page_to_pfn(page), 1 << order);
}

1245
#ifdef CONFIG_CONTIG_ALLOC
1246 1247
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
		int nid, nodemask_t *nodemask)
1248
{
1249
	unsigned long nr_pages = 1UL << huge_page_order(h);
1250

1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265
	if (IS_ENABLED(CONFIG_CMA)) {
		struct page *page;
		int node;

		for_each_node_mask(node, *nodemask) {
			if (!hugetlb_cma[node])
				continue;

			page = cma_alloc(hugetlb_cma[node], nr_pages,
					 huge_page_order(h), true);
			if (page)
				return page;
		}
	}

1266
	return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1267 1268 1269
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1270
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1271 1272 1273 1274 1275 1276 1277
#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 */
1278

1279
#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1280
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1281 1282 1283 1284
					int nid, nodemask_t *nodemask)
{
	return NULL;
}
1285
static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1286
static inline void destroy_compound_gigantic_page(struct page *page,
1287
						unsigned int order) { }
1288 1289
#endif

1290
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1291 1292
{
	int i;
1293

1294
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1295
		return;
1296

1297 1298 1299
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
1300 1301
		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
1302 1303
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1304
	}
1305
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1306
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1307
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1308
	set_page_refcounted(page);
1309
	if (hstate_is_gigantic(h)) {
1310 1311 1312 1313 1314
		/*
		 * Temporarily drop the hugetlb_lock, because
		 * we might block in free_gigantic_page().
		 */
		spin_unlock(&hugetlb_lock);
1315 1316
		destroy_compound_gigantic_page(page, huge_page_order(h));
		free_gigantic_page(page, huge_page_order(h));
1317
		spin_lock(&hugetlb_lock);
1318 1319 1320
	} else {
		__free_pages(page, huge_page_order(h));
	}
A
Adam Litke 已提交
1321 1322
}

1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333
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;
}

1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358
/*
 * 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]);
}

1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380
/*
 * 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;
}

1381
static void __free_huge_page(struct page *page)
1382
{
1383 1384 1385 1386
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1387
	struct hstate *h = page_hstate(page);
1388
	int nid = page_to_nid(page);
1389 1390
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1391
	bool restore_reserve;
1392

1393 1394
	VM_BUG_ON_PAGE(page_count(page), page);
	VM_BUG_ON_PAGE(page_mapcount(page), page);
1395 1396 1397

	set_page_private(page, 0);
	page->mapping = NULL;
1398
	restore_reserve = PagePrivate(page);
1399
	ClearPagePrivate(page);
1400

1401
	/*
1402 1403 1404 1405 1406 1407
	 * 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.
1408
	 */
1409 1410 1411 1412 1413 1414 1415 1416 1417 1418
	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;
	}
1419

1420
	spin_lock(&hugetlb_lock);
1421
	clear_page_huge_active(page);
1422 1423
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1424 1425
	hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
					  pages_per_huge_page(h), page);
1426 1427 1428
	if (restore_reserve)
		h->resv_huge_pages++;

1429 1430 1431 1432 1433
	if (PageHugeTemporary(page)) {
		list_del(&page->lru);
		ClearPageHugeTemporary(page);
		update_and_free_page(h, page);
	} else if (h->surplus_huge_pages_node[nid]) {
1434 1435
		/* remove the page from active list */
		list_del(&page->lru);
1436 1437 1438
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1439
	} else {
1440
		arch_clear_hugepage_flags(page);
1441
		enqueue_huge_page(h, page);
1442
	}
1443 1444 1445
	spin_unlock(&hugetlb_lock);
}

1446 1447 1448 1449 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
/*
 * 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);
}

1494
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1495
{
1496
	INIT_LIST_HEAD(&page->lru);
1497
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1498
	spin_lock(&hugetlb_lock);
1499
	set_hugetlb_cgroup(page, NULL);
1500
	set_hugetlb_cgroup_rsvd(page, NULL);
1501 1502
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1503 1504 1505
	spin_unlock(&hugetlb_lock);
}

1506
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1507 1508 1509 1510 1511 1512 1513
{
	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);
1514
	__ClearPageReserved(page);
1515
	__SetPageHead(page);
1516
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1517 1518 1519 1520
		/*
		 * 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
1521
		 * too.  Otherwise drivers using get_user_pages() to access tail
1522 1523 1524 1525 1526 1527 1528 1529
		 * 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);
1530
		set_page_count(p, 0);
1531
		set_compound_head(p, page);
1532
	}
1533
	atomic_set(compound_mapcount_ptr(page), -1);
1534 1535 1536

	if (hpage_pincount_available(page))
		atomic_set(compound_pincount_ptr(page), 0);
1537 1538
}

A
Andrew Morton 已提交
1539 1540 1541 1542 1543
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1544 1545 1546 1547 1548 1549
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1550
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1551
}
1552 1553
EXPORT_SYMBOL_GPL(PageHuge);

1554 1555 1556 1557 1558 1559 1560 1561 1562
/*
 * 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;

1563
	return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1564 1565
}

1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 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
/*
 * 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);
	pgoff_end = pgoff_start + hpage_nr_pages(hpage) - 1;
	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;
}

1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682
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;
}

1683
static struct page *alloc_buddy_huge_page(struct hstate *h,
1684 1685
		gfp_t gfp_mask, int nid, nodemask_t *nmask,
		nodemask_t *node_alloc_noretry)
L
Linus Torvalds 已提交
1686
{
1687
	int order = huge_page_order(h);
L
Linus Torvalds 已提交
1688
	struct page *page;
1689
	bool alloc_try_hard = true;
1690

1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702
	/*
	 * 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;
1703 1704 1705 1706 1707 1708 1709
	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);
1710

1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726
	/*
	 * 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);

1727 1728 1729
	return page;
}

1730 1731 1732 1733 1734
/*
 * 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,
1735 1736
		gfp_t gfp_mask, int nid, nodemask_t *nmask,
		nodemask_t *node_alloc_noretry)
1737 1738 1739 1740 1741 1742 1743
{
	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,
1744
				nid, nmask, node_alloc_noretry);
1745 1746 1747 1748 1749 1750 1751 1752 1753 1754
	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;
}

1755 1756 1757 1758
/*
 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
 * manner.
 */
1759 1760
static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
				nodemask_t *node_alloc_noretry)
1761 1762 1763
{
	struct page *page;
	int nr_nodes, node;
1764
	gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1765 1766

	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1767 1768
		page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
						node_alloc_noretry);
1769
		if (page)
1770 1771 1772
			break;
	}

1773 1774
	if (!page)
		return 0;
1775

1776 1777 1778
	put_page(page); /* free it into the hugepage allocator */

	return 1;
1779 1780
}

1781 1782 1783 1784 1785 1786
/*
 * 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.
 */
1787 1788
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1789
{
1790
	int nr_nodes, node;
1791 1792
	int ret = 0;

1793
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1794 1795 1796 1797
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1798 1799
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1800
			struct page *page =
1801
				list_entry(h->hugepage_freelists[node].next,
1802 1803 1804
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1805
			h->free_huge_pages_node[node]--;
1806 1807
			if (acct_surplus) {
				h->surplus_huge_pages--;
1808
				h->surplus_huge_pages_node[node]--;
1809
			}
1810 1811
			update_and_free_page(h, page);
			ret = 1;
1812
			break;
1813
		}
1814
	}
1815 1816 1817 1818

	return ret;
}

1819 1820
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
1821 1822 1823 1824 1825 1826 1827
 * 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)
1828
 */
1829
int dissolve_free_huge_page(struct page *page)
1830
{
1831
	int rc = -EBUSY;
1832

1833 1834 1835 1836
	/* Not to disrupt normal path by vainly holding hugetlb_lock */
	if (!PageHuge(page))
		return 0;

1837
	spin_lock(&hugetlb_lock);
1838 1839 1840 1841 1842 1843
	if (!PageHuge(page)) {
		rc = 0;
		goto out;
	}

	if (!page_count(page)) {
1844 1845 1846
		struct page *head = compound_head(page);
		struct hstate *h = page_hstate(head);
		int nid = page_to_nid(head);
1847
		if (h->free_huge_pages - h->resv_huge_pages == 0)
1848
			goto out;
1849 1850 1851 1852 1853 1854 1855 1856
		/*
		 * 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);
		}
1857
		list_del(&head->lru);
1858 1859
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
1860
		h->max_huge_pages--;
1861
		update_and_free_page(h, head);
1862
		rc = 0;
1863
	}
1864
out:
1865
	spin_unlock(&hugetlb_lock);
1866
	return rc;
1867 1868 1869 1870 1871
}

/*
 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 * make specified memory blocks removable from the system.
1872 1873
 * Note that this will dissolve a free gigantic hugepage completely, if any
 * part of it lies within the given range.
1874 1875
 * Also note that if dissolve_free_huge_page() returns with an error, all
 * free hugepages that were dissolved before that error are lost.
1876
 */
1877
int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1878 1879
{
	unsigned long pfn;
1880
	struct page *page;
1881
	int rc = 0;
1882

1883
	if (!hugepages_supported())
1884
		return rc;
1885

1886 1887
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
		page = pfn_to_page(pfn);
1888 1889 1890
		rc = dissolve_free_huge_page(page);
		if (rc)
			break;
1891
	}
1892 1893

	return rc;
1894 1895
}

1896 1897 1898
/*
 * Allocates a fresh surplus page from the page allocator.
 */
1899
static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1900
		int nid, nodemask_t *nmask)
1901
{
1902
	struct page *page = NULL;
1903

1904
	if (hstate_is_gigantic(h))
1905 1906
		return NULL;

1907
	spin_lock(&hugetlb_lock);
1908 1909
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
		goto out_unlock;
1910 1911
	spin_unlock(&hugetlb_lock);

1912
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1913
	if (!page)
1914
		return NULL;
1915 1916

	spin_lock(&hugetlb_lock);
1917 1918 1919 1920 1921 1922 1923 1924 1925
	/*
	 * 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);
1926
		spin_unlock(&hugetlb_lock);
1927
		put_page(page);
1928
		return NULL;
1929 1930
	} else {
		h->surplus_huge_pages++;
1931
		h->surplus_huge_pages_node[page_to_nid(page)]++;
1932
	}
1933 1934

out_unlock:
1935
	spin_unlock(&hugetlb_lock);
1936 1937 1938 1939

	return page;
}

1940 1941
struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
				     int nid, nodemask_t *nmask)
1942 1943 1944 1945 1946 1947
{
	struct page *page;

	if (hstate_is_gigantic(h))
		return NULL;

1948
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960
	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;
}

1961 1962 1963
/*
 * Use the VMA's mpolicy to allocate a huge page from the buddy.
 */
D
Dave Hansen 已提交
1964
static
1965
struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1966 1967
		struct vm_area_struct *vma, unsigned long addr)
{
1968 1969 1970 1971 1972 1973 1974
	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);
1975
	page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1976 1977 1978
	mpol_cond_put(mpol);

	return page;
1979 1980
}

1981
/* page migration callback function */
1982 1983
struct page *alloc_huge_page_node(struct hstate *h, int nid)
{
1984
	gfp_t gfp_mask = htlb_alloc_mask(h);
1985
	struct page *page = NULL;
1986

1987 1988 1989
	if (nid != NUMA_NO_NODE)
		gfp_mask |= __GFP_THISNODE;

1990
	spin_lock(&hugetlb_lock);
1991
	if (h->free_huge_pages - h->resv_huge_pages > 0)
1992
		page = dequeue_huge_page_nodemask(h, gfp_mask, nid, NULL);
1993 1994
	spin_unlock(&hugetlb_lock);

1995
	if (!page)
1996
		page = alloc_migrate_huge_page(h, gfp_mask, nid, NULL);
1997 1998 1999 2000

	return page;
}

2001
/* page migration callback function */
2002 2003
struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
		nodemask_t *nmask)
2004
{
2005
	gfp_t gfp_mask = htlb_alloc_mask(h);
2006 2007 2008

	spin_lock(&hugetlb_lock);
	if (h->free_huge_pages - h->resv_huge_pages > 0) {
2009 2010 2011 2012 2013 2014
		struct page *page;

		page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
		if (page) {
			spin_unlock(&hugetlb_lock);
			return page;
2015 2016 2017 2018
		}
	}
	spin_unlock(&hugetlb_lock);

2019
	return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
2020 2021
}

2022
/* mempolicy aware migration callback */
2023 2024
struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
		unsigned long address)
2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039
{
	struct mempolicy *mpol;
	nodemask_t *nodemask;
	struct page *page;
	gfp_t gfp_mask;
	int node;

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

	return page;
}

2040
/*
L
Lucas De Marchi 已提交
2041
 * Increase the hugetlb pool such that it can accommodate a reservation
2042 2043
 * of size 'delta'.
 */
2044
static int gather_surplus_pages(struct hstate *h, int delta)
2045
	__must_hold(&hugetlb_lock)
2046 2047 2048 2049 2050
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
2051
	bool alloc_ok = true;
2052

2053
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2054
	if (needed <= 0) {
2055
		h->resv_huge_pages += delta;
2056
		return 0;
2057
	}
2058 2059 2060 2061 2062 2063 2064 2065

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
2066
		page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
2067
				NUMA_NO_NODE, NULL);
2068 2069 2070 2071
		if (!page) {
			alloc_ok = false;
			break;
		}
2072
		list_add(&page->lru, &surplus_list);
2073
		cond_resched();
2074
	}
2075
	allocated += i;
2076 2077 2078 2079 2080 2081

	/*
	 * 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);
2082 2083
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
2084 2085 2086 2087 2088 2089 2090 2091 2092 2093
	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;
	}
2094 2095
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
2096
	 * needed to accommodate the reservation.  Add the appropriate number
2097
	 * of pages to the hugetlb pool and free the extras back to the buddy
2098 2099 2100
	 * 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.
2101 2102
	 */
	needed += allocated;
2103
	h->resv_huge_pages += delta;
2104
	ret = 0;
2105

2106
	/* Free the needed pages to the hugetlb pool */
2107
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2108 2109
		if ((--needed) < 0)
			break;
2110 2111 2112 2113 2114
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
2115
		VM_BUG_ON_PAGE(page_count(page), page);
2116
		enqueue_huge_page(h, page);
2117
	}
2118
free:
2119
	spin_unlock(&hugetlb_lock);
2120 2121

	/* Free unnecessary surplus pages to the buddy allocator */
2122 2123
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
2124
	spin_lock(&hugetlb_lock);
2125 2126 2127 2128 2129

	return ret;
}

/*
2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141
 * 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.
2142
 */
2143 2144
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
2145 2146 2147
{
	unsigned long nr_pages;

2148
	/* Cannot return gigantic pages currently */
2149
	if (hstate_is_gigantic(h))
2150
		goto out;
2151

2152 2153 2154 2155
	/*
	 * Part (or even all) of the reservation could have been backed
	 * by pre-allocated pages. Only free surplus pages.
	 */
2156
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2157

2158 2159
	/*
	 * We want to release as many surplus pages as possible, spread
2160 2161 2162 2163 2164
	 * evenly across all nodes with memory. Iterate across these nodes
	 * until we can no longer free unreserved surplus pages. This occurs
	 * when the nodes with surplus pages have no free pages.
	 * free_pool_huge_page() will balance the the freed pages across the
	 * on-line nodes with memory and will handle the hstate accounting.
2165 2166 2167 2168
	 *
	 * 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.
2169 2170
	 */
	while (nr_pages--) {
2171 2172
		h->resv_huge_pages--;
		unused_resv_pages--;
2173
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
2174
			goto out;
2175
		cond_resched_lock(&hugetlb_lock);
2176
	}
2177 2178 2179 2180

out:
	/* Fully uncommit the reservation */
	h->resv_huge_pages -= unused_resv_pages;
2181 2182
}

2183

2184
/*
2185
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2186
 * are used by the huge page allocation routines to manage reservations.
2187 2188 2189 2190 2191 2192
 *
 * 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
2193 2194 2195
 * 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.
2196 2197 2198 2199 2200 2201
 *
 * 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.
2202 2203 2204 2205 2206
 *
 * 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.
2207
 */
2208 2209 2210
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
2211
	VMA_END_RESV,
2212
	VMA_ADD_RESV,
2213
};
2214 2215
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
2216
				enum vma_resv_mode mode)
2217
{
2218 2219
	struct resv_map *resv;
	pgoff_t idx;
2220
	long ret;
2221
	long dummy_out_regions_needed;
2222

2223 2224
	resv = vma_resv_map(vma);
	if (!resv)
2225
		return 1;
2226

2227
	idx = vma_hugecache_offset(h, vma, addr);
2228 2229
	switch (mode) {
	case VMA_NEEDS_RESV:
2230 2231 2232 2233 2234 2235
		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);
2236 2237
		break;
	case VMA_COMMIT_RESV:
2238
		ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2239 2240
		/* region_add calls of range 1 should never fail. */
		VM_BUG_ON(ret < 0);
2241
		break;
2242
	case VMA_END_RESV:
2243
		region_abort(resv, idx, idx + 1, 1);
2244 2245
		ret = 0;
		break;
2246
	case VMA_ADD_RESV:
2247
		if (vma->vm_flags & VM_MAYSHARE) {
2248
			ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2249 2250 2251 2252
			/* region_add calls of range 1 should never fail. */
			VM_BUG_ON(ret < 0);
		} else {
			region_abort(resv, idx, idx + 1, 1);
2253 2254 2255
			ret = region_del(resv, idx, idx + 1);
		}
		break;
2256 2257 2258
	default:
		BUG();
	}
2259

2260
	if (vma->vm_flags & VM_MAYSHARE)
2261
		return ret;
2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280
	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;
	}
2281
	else
2282
		return ret < 0 ? ret : 0;
2283
}
2284 2285

static long vma_needs_reservation(struct hstate *h,
2286
			struct vm_area_struct *vma, unsigned long addr)
2287
{
2288
	return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2289
}
2290

2291 2292 2293
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
2294 2295 2296
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

2297
static void vma_end_reservation(struct hstate *h,
2298 2299
			struct vm_area_struct *vma, unsigned long addr)
{
2300
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
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 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352
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);
	}
}

2353
struct page *alloc_huge_page(struct vm_area_struct *vma,
2354
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
2355
{
2356
	struct hugepage_subpool *spool = subpool_vma(vma);
2357
	struct hstate *h = hstate_vma(vma);
2358
	struct page *page;
2359 2360
	long map_chg, map_commit;
	long gbl_chg;
2361 2362
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
2363
	bool deferred_reserve;
2364

2365
	idx = hstate_index(h);
2366
	/*
2367 2368 2369
	 * 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).
2370
	 */
2371 2372
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
2373
		return ERR_PTR(-ENOMEM);
2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384

	/*
	 * 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) {
2385
			vma_end_reservation(h, vma, addr);
2386
			return ERR_PTR(-ENOSPC);
2387
		}
L
Linus Torvalds 已提交
2388

2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400
		/*
		 * 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;
	}

2401 2402 2403 2404 2405 2406 2407 2408 2409 2410
	/* 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;
	}

2411
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2412
	if (ret)
2413
		goto out_uncharge_cgroup_reservation;
2414

L
Linus Torvalds 已提交
2415
	spin_lock(&hugetlb_lock);
2416 2417 2418 2419 2420 2421
	/*
	 * 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);
2422
	if (!page) {
2423
		spin_unlock(&hugetlb_lock);
2424
		page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2425 2426
		if (!page)
			goto out_uncharge_cgroup;
2427 2428 2429 2430
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
2431 2432
		spin_lock(&hugetlb_lock);
		list_move(&page->lru, &h->hugepage_activelist);
2433
		/* Fall through */
K
Ken Chen 已提交
2434
	}
2435
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2436 2437 2438 2439 2440 2441 2442 2443
	/* 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);
	}

2444
	spin_unlock(&hugetlb_lock);
2445

2446
	set_page_private(page, (unsigned long)spool);
2447

2448 2449
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463
		/*
		 * 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);
	}
2464
	return page;
2465 2466 2467

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2468 2469 2470 2471
out_uncharge_cgroup_reservation:
	if (deferred_reserve)
		hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
						    h_cg);
2472
out_subpool_put:
2473
	if (map_chg || avoid_reserve)
2474
		hugepage_subpool_put_pages(spool, 1);
2475
	vma_end_reservation(h, vma, addr);
2476
	return ERR_PTR(-ENOSPC);
2477 2478
}

2479 2480 2481
int alloc_bootmem_huge_page(struct hstate *h)
	__attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
int __alloc_bootmem_huge_page(struct hstate *h)
2482 2483
{
	struct huge_bootmem_page *m;
2484
	int nr_nodes, node;
2485

2486
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2487 2488
		void *addr;

2489
		addr = memblock_alloc_try_nid_raw(
2490
				huge_page_size(h), huge_page_size(h),
2491
				0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2492 2493 2494 2495 2496 2497 2498
		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;
2499
			goto found;
2500 2501 2502 2503 2504
		}
	}
	return 0;

found:
2505
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2506
	/* Put them into a private list first because mem_map is not up yet */
2507
	INIT_LIST_HEAD(&m->list);
2508 2509 2510 2511 2512
	list_add(&m->list, &huge_boot_pages);
	m->hstate = h;
	return 1;
}

2513 2514
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
2515 2516 2517 2518 2519 2520 2521
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

2522 2523 2524 2525 2526 2527
/* 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) {
2528
		struct page *page = virt_to_page(m);
2529
		struct hstate *h = m->hstate;
2530

2531
		WARN_ON(page_count(page) != 1);
2532
		prep_compound_huge_page(page, h->order);
2533
		WARN_ON(PageReserved(page));
2534
		prep_new_huge_page(h, page, page_to_nid(page));
2535 2536
		put_page(page); /* free it into the hugepage allocator */

2537 2538 2539 2540 2541 2542
		/*
		 * 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.
		 */
2543
		if (hstate_is_gigantic(h))
2544
			adjust_managed_page_count(page, 1 << h->order);
2545
		cond_resched();
2546 2547 2548
	}
}

2549
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2550 2551
{
	unsigned long i;
2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570
	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);
2571

2572
	for (i = 0; i < h->max_huge_pages; ++i) {
2573
		if (hstate_is_gigantic(h)) {
2574 2575 2576 2577
			if (IS_ENABLED(CONFIG_CMA) && hugetlb_cma[0]) {
				pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
				break;
			}
2578 2579
			if (!alloc_bootmem_huge_page(h))
				break;
2580
		} else if (!alloc_pool_huge_page(h,
2581 2582
					 &node_states[N_MEMORY],
					 node_alloc_noretry))
L
Linus Torvalds 已提交
2583
			break;
2584
		cond_resched();
L
Linus Torvalds 已提交
2585
	}
2586 2587 2588
	if (i < h->max_huge_pages) {
		char buf[32];

2589
		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2590 2591 2592 2593
		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;
	}
2594 2595

	kfree(node_alloc_noretry);
2596 2597 2598 2599 2600 2601 2602
}

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

	for_each_hstate(h) {
2603 2604 2605
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2606
		/* oversize hugepages were init'ed in early boot */
2607
		if (!hstate_is_gigantic(h))
2608
			hugetlb_hstate_alloc_pages(h);
2609
	}
2610
	VM_BUG_ON(minimum_order == UINT_MAX);
2611 2612 2613 2614 2615 2616 2617
}

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

	for_each_hstate(h) {
A
Andi Kleen 已提交
2618
		char buf[32];
2619 2620

		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2621
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2622
			buf, h->free_huge_pages);
2623 2624 2625
	}
}

L
Linus Torvalds 已提交
2626
#ifdef CONFIG_HIGHMEM
2627 2628
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2629
{
2630 2631
	int i;

2632
	if (hstate_is_gigantic(h))
2633 2634
		return;

2635
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2636
		struct page *page, *next;
2637 2638 2639
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2640
				return;
L
Linus Torvalds 已提交
2641 2642 2643
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2644
			update_and_free_page(h, page);
2645 2646
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2647 2648 2649 2650
		}
	}
}
#else
2651 2652
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2653 2654 2655 2656
{
}
#endif

2657 2658 2659 2660 2661
/*
 * 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.
 */
2662 2663
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2664
{
2665
	int nr_nodes, node;
2666 2667 2668

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

2669 2670 2671 2672
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2673
		}
2674 2675 2676 2677 2678
	} 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;
2679
		}
2680 2681
	}
	return 0;
2682

2683 2684 2685 2686
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2687 2688
}

2689
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2690
static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2691
			      nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2692
{
2693
	unsigned long min_count, ret;
2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704
	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
2705

2706 2707
	spin_lock(&hugetlb_lock);

2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727
	/*
	 * 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;
	}

2728 2729 2730 2731 2732 2733 2734 2735 2736 2737
	/*
	 * 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);
2738
			NODEMASK_FREE(node_alloc_noretry);
2739 2740 2741 2742
			return -EINVAL;
		}
		/* Fall through to decrease pool */
	}
2743

2744 2745 2746 2747
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2748
	 *
2749
	 * We might race with alloc_surplus_huge_page() here and be unable
2750 2751 2752 2753
	 * 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.
2754
	 */
2755
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2756
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2757 2758 2759
			break;
	}

2760
	while (count > persistent_huge_pages(h)) {
2761 2762 2763 2764 2765 2766
		/*
		 * 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);
2767 2768 2769 2770

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

2771 2772
		ret = alloc_pool_huge_page(h, nodes_allowed,
						node_alloc_noretry);
2773 2774 2775 2776
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2777 2778 2779
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2780 2781 2782 2783 2784 2785 2786 2787
	}

	/*
	 * 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.
2788 2789 2790 2791
	 *
	 * 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
2792
	 * alloc_surplus_huge_page() is checking the global counter,
2793 2794 2795
	 * 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.
2796
	 */
2797
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2798
	min_count = max(count, min_count);
2799
	try_to_free_low(h, min_count, nodes_allowed);
2800
	while (min_count < persistent_huge_pages(h)) {
2801
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2802
			break;
2803
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2804
	}
2805
	while (count < persistent_huge_pages(h)) {
2806
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2807 2808 2809
			break;
	}
out:
2810
	h->max_huge_pages = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2811
	spin_unlock(&hugetlb_lock);
2812

2813 2814
	NODEMASK_FREE(node_alloc_noretry);

2815
	return 0;
L
Linus Torvalds 已提交
2816 2817
}

2818 2819 2820 2821 2822 2823 2824 2825 2826 2827
#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];

2828 2829 2830
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2831 2832
{
	int i;
2833

2834
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2835 2836 2837
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2838
			return &hstates[i];
2839 2840 2841
		}

	return kobj_to_node_hstate(kobj, nidp);
2842 2843
}

2844
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2845 2846
					struct kobj_attribute *attr, char *buf)
{
2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857
	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);
2858
}
2859

2860 2861 2862
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2863 2864
{
	int err;
2865
	nodemask_t nodes_allowed, *n_mask;
2866

2867 2868
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
		return -EINVAL;
2869

2870 2871 2872 2873 2874
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
2875 2876 2877 2878 2879
				init_nodemask_of_mempolicy(&nodes_allowed)))
			n_mask = &node_states[N_MEMORY];
		else
			n_mask = &nodes_allowed;
	} else {
2880
		/*
2881 2882
		 * Node specific request.  count adjustment happens in
		 * set_max_huge_pages() after acquiring hugetlb_lock.
2883
		 */
2884 2885
		init_nodemask_of_node(&nodes_allowed, nid);
		n_mask = &nodes_allowed;
2886
	}
2887

2888
	err = set_max_huge_pages(h, count, nid, n_mask);
2889

2890
	return err ? err : len;
2891 2892
}

2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909
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);
}

2910 2911 2912 2913 2914 2915 2916 2917 2918
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)
{
2919
	return nr_hugepages_store_common(false, kobj, buf, len);
2920 2921 2922
}
HSTATE_ATTR(nr_hugepages);

2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937
#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)
{
2938
	return nr_hugepages_store_common(true, kobj, buf, len);
2939 2940 2941 2942 2943
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2944 2945 2946
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2947
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2948 2949
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2950

2951 2952 2953 2954 2955
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;
2956
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2957

2958
	if (hstate_is_gigantic(h))
2959 2960
		return -EINVAL;

2961
	err = kstrtoul(buf, 10, &input);
2962
	if (err)
2963
		return err;
2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975

	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)
{
2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986
	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);
2987 2988 2989 2990 2991 2992
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2993
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2994 2995 2996 2997 2998 2999 3000
	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)
{
3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011
	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);
3012 3013 3014 3015 3016 3017 3018 3019 3020
}
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,
3021 3022 3023
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
3024 3025 3026
	NULL,
};

3027
static const struct attribute_group hstate_attr_group = {
3028 3029 3030
	.attrs = hstate_attrs,
};

J
Jeff Mahoney 已提交
3031 3032
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
3033
				    const struct attribute_group *hstate_attr_group)
3034 3035
{
	int retval;
3036
	int hi = hstate_index(h);
3037

3038 3039
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
3040 3041
		return -ENOMEM;

3042
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3043
	if (retval)
3044
		kobject_put(hstate_kobjs[hi]);
3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058

	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) {
3059 3060
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
3061
		if (err)
3062
			pr_err("HugeTLB: Unable to add hstate %s", h->name);
3063 3064 3065
	}
}

3066 3067 3068 3069
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3070 3071 3072
 * 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
3073 3074 3075 3076 3077 3078
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
3079
static struct node_hstate node_hstates[MAX_NUMNODES];
3080 3081

/*
3082
 * A subset of global hstate attributes for node devices
3083 3084 3085 3086 3087 3088 3089 3090
 */
static struct attribute *per_node_hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
	NULL,
};

3091
static const struct attribute_group per_node_hstate_attr_group = {
3092 3093 3094 3095
	.attrs = per_node_hstate_attrs,
};

/*
3096
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118
 * 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;
}

/*
3119
 * Unregister hstate attributes from a single node device.
3120 3121
 * No-op if no hstate attributes attached.
 */
3122
static void hugetlb_unregister_node(struct node *node)
3123 3124
{
	struct hstate *h;
3125
	struct node_hstate *nhs = &node_hstates[node->dev.id];
3126 3127

	if (!nhs->hugepages_kobj)
3128
		return;		/* no hstate attributes */
3129

3130 3131 3132 3133 3134
	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;
3135
		}
3136
	}
3137 3138 3139 3140 3141 3142 3143

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


/*
3144
 * Register hstate attributes for a single node device.
3145 3146
 * No-op if attributes already registered.
 */
3147
static void hugetlb_register_node(struct node *node)
3148 3149
{
	struct hstate *h;
3150
	struct node_hstate *nhs = &node_hstates[node->dev.id];
3151 3152 3153 3154 3155 3156
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3157
							&node->dev.kobj);
3158 3159 3160 3161 3162 3163 3164 3165
	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) {
3166
			pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3167
				h->name, node->dev.id);
3168 3169 3170 3171 3172 3173 3174
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
3175
 * hugetlb init time:  register hstate attributes for all registered node
3176 3177
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
3178
 */
3179
static void __init hugetlb_register_all_nodes(void)
3180 3181 3182
{
	int nid;

3183
	for_each_node_state(nid, N_MEMORY) {
3184
		struct node *node = node_devices[nid];
3185
		if (node->dev.id == nid)
3186 3187 3188 3189
			hugetlb_register_node(node);
	}

	/*
3190
	 * Let the node device driver know we're here so it can
3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209
	 * [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

3210 3211
static int __init hugetlb_init(void)
{
3212 3213
	int i;

3214 3215 3216
	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");
3217
		return 0;
3218
	}
3219

3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247
	/*
	 * 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;
3248
		}
3249
	}
3250

3251
	hugetlb_cma_check();
3252
	hugetlb_init_hstates();
3253
	gather_bootmem_prealloc();
3254 3255 3256
	report_hugepages();

	hugetlb_sysfs_init();
3257
	hugetlb_register_all_nodes();
3258
	hugetlb_cgroup_file_init();
3259

3260 3261 3262 3263 3264
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
3265
	hugetlb_fault_mutex_table =
3266 3267
		kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
			      GFP_KERNEL);
3268
	BUG_ON(!hugetlb_fault_mutex_table);
3269 3270

	for (i = 0; i < num_fault_mutexes; i++)
3271
		mutex_init(&hugetlb_fault_mutex_table[i]);
3272 3273
	return 0;
}
3274
subsys_initcall(hugetlb_init);
3275

3276 3277
/* Overwritten by architectures with more huge page sizes */
bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3278
{
3279
	return size == HPAGE_SIZE;
3280 3281
}

3282
void __init hugetlb_add_hstate(unsigned int order)
3283 3284
{
	struct hstate *h;
3285 3286
	unsigned long i;

3287 3288 3289
	if (size_to_hstate(PAGE_SIZE << order)) {
		return;
	}
3290
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3291
	BUG_ON(order == 0);
3292
	h = &hstates[hugetlb_max_hstate++];
3293 3294
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
3295 3296 3297 3298
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3299
	INIT_LIST_HEAD(&h->hugepage_activelist);
3300 3301
	h->next_nid_to_alloc = first_memory_node;
	h->next_nid_to_free = first_memory_node;
3302 3303
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
3304

3305 3306 3307
	parsed_hstate = h;
}

3308 3309 3310 3311 3312 3313 3314 3315
/*
 * 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)
3316 3317
{
	unsigned long *mhp;
3318
	static unsigned long *last_mhp;
3319

3320
	if (!parsed_valid_hugepagesz) {
3321
		pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3322
		parsed_valid_hugepagesz = true;
3323
		return 0;
3324
	}
3325

3326
	/*
3327 3328 3329 3330
	 * !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.
3331
	 */
3332
	else if (!hugetlb_max_hstate)
3333 3334 3335 3336
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

3337
	if (mhp == last_mhp) {
3338 3339
		pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
		return 0;
3340 3341
	}

3342 3343 3344
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

3345 3346 3347 3348 3349
	/*
	 * 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.
	 */
3350
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
3351 3352 3353 3354
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

3355 3356
	return 1;
}
3357
__setup("hugepages=", hugepages_setup);
3358

3359 3360 3361 3362 3363 3364 3365
/*
 * 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.
 */
3366
static int __init hugepagesz_setup(char *s)
3367
{
3368
	unsigned long size;
3369 3370 3371
	struct hstate *h;

	parsed_valid_hugepagesz = false;
3372 3373 3374
	size = (unsigned long)memparse(s, NULL);

	if (!arch_hugetlb_valid_size(size)) {
3375
		pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3376 3377 3378
		return 0;
	}

3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401
	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;
3402 3403
	}

3404
	hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3405
	parsed_valid_hugepagesz = true;
3406 3407
	return 1;
}
3408 3409
__setup("hugepagesz=", hugepagesz_setup);

3410 3411 3412 3413
/*
 * default_hugepagesz command line input
 * Only one instance of default_hugepagesz allowed on command line.
 */
3414
static int __init default_hugepagesz_setup(char *s)
3415
{
3416 3417
	unsigned long size;

3418 3419 3420 3421 3422 3423
	parsed_valid_hugepagesz = false;
	if (parsed_default_hugepagesz) {
		pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
		return 0;
	}

3424 3425 3426
	size = (unsigned long)memparse(s, NULL);

	if (!arch_hugetlb_valid_size(size)) {
3427
		pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3428 3429 3430
		return 0;
	}

3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449
	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;
	}

3450 3451
	return 1;
}
3452
__setup("default_hugepagesz=", default_hugepagesz_setup);
3453

3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465
static unsigned int cpuset_mems_nr(unsigned int *array)
{
	int node;
	unsigned int nr = 0;

	for_each_node_mask(node, cpuset_current_mems_allowed)
		nr += array[node];

	return nr;
}

#ifdef CONFIG_SYSCTL
3466 3467
static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
			 struct ctl_table *table, int write,
3468
			 void *buffer, size_t *length, loff_t *ppos)
L
Linus Torvalds 已提交
3469
{
3470
	struct hstate *h = &default_hstate;
3471
	unsigned long tmp = h->max_huge_pages;
3472
	int ret;
3473

3474
	if (!hugepages_supported())
3475
		return -EOPNOTSUPP;
3476

3477 3478
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
3479 3480 3481
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
3482

3483 3484 3485
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
3486 3487
out:
	return ret;
L
Linus Torvalds 已提交
3488
}
3489

3490
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3491
			  void *buffer, size_t *length, loff_t *ppos)
3492 3493 3494 3495 3496 3497 3498 3499
{

	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,
3500
			  void *buffer, size_t *length, loff_t *ppos)
3501 3502 3503 3504 3505 3506
{
	return hugetlb_sysctl_handler_common(true, table, write,
							buffer, length, ppos);
}
#endif /* CONFIG_NUMA */

3507
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3508
		void *buffer, size_t *length, loff_t *ppos)
3509
{
3510
	struct hstate *h = &default_hstate;
3511
	unsigned long tmp;
3512
	int ret;
3513

3514
	if (!hugepages_supported())
3515
		return -EOPNOTSUPP;
3516

3517
	tmp = h->nr_overcommit_huge_pages;
3518

3519
	if (write && hstate_is_gigantic(h))
3520 3521
		return -EINVAL;

3522 3523
	table->data = &tmp;
	table->maxlen = sizeof(unsigned long);
3524 3525 3526
	ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
	if (ret)
		goto out;
3527 3528 3529 3530 3531 3532

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
3533 3534
out:
	return ret;
3535 3536
}

L
Linus Torvalds 已提交
3537 3538
#endif /* CONFIG_SYSCTL */

3539
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
3540
{
3541 3542 3543
	struct hstate *h;
	unsigned long total = 0;

3544 3545
	if (!hugepages_supported())
		return;
3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566

	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
3567 3568 3569 3570
}

int hugetlb_report_node_meminfo(int nid, char *buf)
{
3571
	struct hstate *h = &default_hstate;
3572 3573
	if (!hugepages_supported())
		return 0;
L
Linus Torvalds 已提交
3574 3575
	return sprintf(buf,
		"Node %d HugePages_Total: %5u\n"
3576 3577
		"Node %d HugePages_Free:  %5u\n"
		"Node %d HugePages_Surp:  %5u\n",
3578 3579 3580
		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
3581 3582
}

3583 3584 3585 3586 3587
void hugetlb_show_meminfo(void)
{
	struct hstate *h;
	int nid;

3588 3589 3590
	if (!hugepages_supported())
		return;

3591 3592 3593 3594 3595 3596 3597 3598 3599 3600
	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));
}

3601 3602 3603 3604 3605 3606
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
3607 3608 3609
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
3610 3611 3612 3613 3614 3615
	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
3616 3617
}

3618
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640
{
	int ret = -ENOMEM;

	spin_lock(&hugetlb_lock);
	/*
	 * When cpuset is configured, it breaks the strict hugetlb page
	 * reservation as the accounting is done on a global variable. Such
	 * reservation is completely rubbish in the presence of cpuset because
	 * the reservation is not checked against page availability for the
	 * current cpuset. Application can still potentially OOM'ed by kernel
	 * with lack of free htlb page in cpuset that the task is in.
	 * Attempt to enforce strict accounting with cpuset is almost
	 * impossible (or too ugly) because cpuset is too fluid that
	 * task or memory node can be dynamically moved between cpusets.
	 *
	 * The change of semantics for shared hugetlb mapping with cpuset is
	 * undesirable. However, in order to preserve some of the semantics,
	 * we fall back to check against current free page availability as
	 * a best attempt and hopefully to minimize the impact of changing
	 * semantics that cpuset has.
	 */
	if (delta > 0) {
3641
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
3642 3643
			goto out;

3644 3645
		if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
3646 3647 3648 3649 3650 3651
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
3652
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
3653 3654 3655 3656 3657 3658

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

3659 3660
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
3661
	struct resv_map *resv = vma_resv_map(vma);
3662 3663 3664 3665 3666

	/*
	 * 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
3667
	 * has a reference to the reservation map it cannot disappear until
3668 3669 3670
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
3671
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3672
		kref_get(&resv->refs);
3673 3674
}

3675 3676
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
3677
	struct hstate *h = hstate_vma(vma);
3678
	struct resv_map *resv = vma_resv_map(vma);
3679
	struct hugepage_subpool *spool = subpool_vma(vma);
3680
	unsigned long reserve, start, end;
3681
	long gbl_reserve;
3682

3683 3684
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
3685

3686 3687
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
3688

3689
	reserve = (end - start) - region_count(resv, start, end);
3690
	hugetlb_cgroup_uncharge_counter(resv, start, end);
3691
	if (reserve) {
3692 3693 3694 3695 3696 3697
		/*
		 * 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);
3698
	}
3699 3700

	kref_put(&resv->refs, resv_map_release);
3701 3702
}

3703 3704 3705 3706 3707 3708 3709
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;
}

3710 3711 3712 3713 3714 3715 3716
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
3717 3718 3719 3720 3721 3722
/*
 * 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.
 */
3723
static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
L
Linus Torvalds 已提交
3724 3725
{
	BUG();
N
Nick Piggin 已提交
3726
	return 0;
L
Linus Torvalds 已提交
3727 3728
}

3729 3730 3731 3732 3733 3734 3735
/*
 * 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.
 */
3736
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
3737
	.fault = hugetlb_vm_op_fault,
3738
	.open = hugetlb_vm_op_open,
3739
	.close = hugetlb_vm_op_close,
3740
	.split = hugetlb_vm_op_split,
3741
	.pagesize = hugetlb_vm_op_pagesize,
L
Linus Torvalds 已提交
3742 3743
};

3744 3745
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
3746 3747 3748
{
	pte_t entry;

3749
	if (writable) {
3750 3751
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
3752
	} else {
3753 3754
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
3755 3756 3757
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3758
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3759 3760 3761 3762

	return entry;
}

3763 3764 3765 3766 3767
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3768
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3769
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3770
		update_mmu_cache(vma, address, ptep);
3771 3772
}

3773
bool is_hugetlb_entry_migration(pte_t pte)
3774 3775 3776 3777
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3778
		return false;
3779 3780
	swp = pte_to_swp_entry(pte);
	if (non_swap_entry(swp) && is_migration_entry(swp))
3781
		return true;
3782
	else
3783
		return false;
3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797
}

static int is_hugetlb_entry_hwpoisoned(pte_t pte)
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
		return 0;
	swp = pte_to_swp_entry(pte);
	if (non_swap_entry(swp) && is_hwpoison_entry(swp))
		return 1;
	else
		return 0;
}
3798

D
David Gibson 已提交
3799 3800 3801
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
			    struct vm_area_struct *vma)
{
3802
	pte_t *src_pte, *dst_pte, entry, dst_entry;
D
David Gibson 已提交
3803
	struct page *ptepage;
3804
	unsigned long addr;
3805
	int cow;
3806 3807
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3808
	struct address_space *mapping = vma->vm_file->f_mapping;
3809
	struct mmu_notifier_range range;
3810
	int ret = 0;
3811 3812

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3813

3814
	if (cow) {
3815
		mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3816
					vma->vm_start,
3817 3818
					vma->vm_end);
		mmu_notifier_invalidate_range_start(&range);
3819 3820 3821 3822 3823 3824 3825 3826
	} 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);
3827
	}
3828

3829
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3830
		spinlock_t *src_ptl, *dst_ptl;
3831
		src_pte = huge_pte_offset(src, addr, sz);
H
Hugh Dickins 已提交
3832 3833
		if (!src_pte)
			continue;
3834
		dst_pte = huge_pte_alloc(dst, addr, sz);
3835 3836 3837 3838
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3839

3840 3841 3842 3843 3844 3845 3846 3847 3848 3849 3850
		/*
		 * 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))
3851 3852
			continue;

3853 3854 3855
		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);
3856
		entry = huge_ptep_get(src_pte);
3857 3858 3859 3860 3861 3862 3863
		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.
			 */
3864 3865 3866 3867 3868 3869 3870 3871 3872 3873 3874 3875
			;
		} 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);
3876 3877
				set_huge_swap_pte_at(src, addr, src_pte,
						     entry, sz);
3878
			}
3879
			set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3880
		} else {
3881
			if (cow) {
3882 3883 3884 3885 3886
				/*
				 * No need to notify as we are downgrading page
				 * table protection not changing it to point
				 * to a new page.
				 *
3887
				 * See Documentation/vm/mmu_notifier.rst
3888
				 */
3889
				huge_ptep_set_wrprotect(src, addr, src_pte);
3890
			}
3891
			entry = huge_ptep_get(src_pte);
3892 3893
			ptepage = pte_page(entry);
			get_page(ptepage);
3894
			page_dup_rmap(ptepage, true);
3895
			set_huge_pte_at(dst, addr, dst_pte, entry);
3896
			hugetlb_count_add(pages_per_huge_page(h), dst);
3897
		}
3898 3899
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3900 3901
	}

3902
	if (cow)
3903
		mmu_notifier_invalidate_range_end(&range);
3904 3905
	else
		i_mmap_unlock_read(mapping);
3906 3907

	return ret;
D
David Gibson 已提交
3908 3909
}

3910 3911 3912
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
3913 3914 3915
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3916
	pte_t *ptep;
D
David Gibson 已提交
3917
	pte_t pte;
3918
	spinlock_t *ptl;
D
David Gibson 已提交
3919
	struct page *page;
3920 3921
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3922
	struct mmu_notifier_range range;
3923

D
David Gibson 已提交
3924
	WARN_ON(!is_vm_hugetlb_page(vma));
3925 3926
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3927

3928 3929 3930 3931
	/*
	 * This is a hugetlb vma, all the pte entries should point
	 * to huge page.
	 */
3932
	tlb_change_page_size(tlb, sz);
3933
	tlb_start_vma(tlb, vma);
3934 3935 3936 3937

	/*
	 * If sharing possible, alert mmu notifiers of worst case.
	 */
3938 3939
	mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
				end);
3940 3941
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
	mmu_notifier_invalidate_range_start(&range);
3942 3943
	address = start;
	for (; address < end; address += sz) {
3944
		ptep = huge_pte_offset(mm, address, sz);
A
Adam Litke 已提交
3945
		if (!ptep)
3946 3947
			continue;

3948
		ptl = huge_pte_lock(h, mm, ptep);
3949 3950
		if (huge_pmd_unshare(mm, &address, ptep)) {
			spin_unlock(ptl);
3951 3952 3953 3954
			/*
			 * We just unmapped a page of PMDs by clearing a PUD.
			 * The caller's TLB flush range should cover this area.
			 */
3955 3956
			continue;
		}
3957

3958
		pte = huge_ptep_get(ptep);
3959 3960 3961 3962
		if (huge_pte_none(pte)) {
			spin_unlock(ptl);
			continue;
		}
3963 3964

		/*
3965 3966
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3967
		 */
3968
		if (unlikely(!pte_present(pte))) {
3969
			huge_pte_clear(mm, address, ptep, sz);
3970 3971
			spin_unlock(ptl);
			continue;
3972
		}
3973 3974

		page = pte_page(pte);
3975 3976 3977 3978 3979 3980
		/*
		 * 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) {
3981 3982 3983 3984
			if (page != ref_page) {
				spin_unlock(ptl);
				continue;
			}
3985 3986 3987 3988 3989 3990 3991 3992
			/*
			 * 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);
		}

3993
		pte = huge_ptep_get_and_clear(mm, address, ptep);
3994
		tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3995
		if (huge_pte_dirty(pte))
3996
			set_page_dirty(page);
3997

3998
		hugetlb_count_sub(pages_per_huge_page(h), mm);
3999
		page_remove_rmap(page, true);
4000

4001
		spin_unlock(ptl);
4002
		tlb_remove_page_size(tlb, page, huge_page_size(h));
4003 4004 4005 4006 4007
		/*
		 * Bail out after unmapping reference page if supplied
		 */
		if (ref_page)
			break;
4008
	}
4009
	mmu_notifier_invalidate_range_end(&range);
4010
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
4011
}
D
David Gibson 已提交
4012

4013 4014 4015 4016 4017 4018 4019 4020 4021 4022 4023 4024
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
4025
	 * is to clear it before releasing the i_mmap_rwsem. This works
4026
	 * because in the context this is called, the VMA is about to be
4027
	 * destroyed and the i_mmap_rwsem is held.
4028 4029 4030 4031
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

4032
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4033
			  unsigned long end, struct page *ref_page)
4034
{
4035 4036
	struct mm_struct *mm;
	struct mmu_gather tlb;
4037 4038 4039 4040 4041 4042 4043 4044 4045 4046 4047
	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);
4048 4049 4050

	mm = vma->vm_mm;

4051
	tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end);
4052
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4053
	tlb_finish_mmu(&tlb, tlb_start, tlb_end);
4054 4055
}

4056 4057 4058 4059 4060 4061
/*
 * 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.
 */
4062 4063
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
4064
{
4065
	struct hstate *h = hstate_vma(vma);
4066 4067 4068 4069 4070 4071 4072 4073
	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.
	 */
4074
	address = address & huge_page_mask(h);
4075 4076
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
4077
	mapping = vma->vm_file->f_mapping;
4078

4079 4080 4081 4082 4083
	/*
	 * 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
	 */
4084
	i_mmap_lock_write(mapping);
4085
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4086 4087 4088 4089
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

4090 4091 4092 4093 4094 4095 4096 4097
		/*
		 * 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;

4098 4099 4100 4101 4102 4103 4104 4105
		/*
		 * 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))
4106 4107
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
4108
	}
4109
	i_mmap_unlock_write(mapping);
4110 4111
}

4112 4113
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4114 4115 4116
 * 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.
4117
 */
4118
static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4119
		       unsigned long address, pte_t *ptep,
4120
		       struct page *pagecache_page, spinlock_t *ptl)
4121
{
4122
	pte_t pte;
4123
	struct hstate *h = hstate_vma(vma);
4124
	struct page *old_page, *new_page;
4125 4126
	int outside_reserve = 0;
	vm_fault_t ret = 0;
4127
	unsigned long haddr = address & huge_page_mask(h);
4128
	struct mmu_notifier_range range;
4129

4130
	pte = huge_ptep_get(ptep);
4131 4132
	old_page = pte_page(pte);

4133
retry_avoidcopy:
4134 4135
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
4136
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4137
		page_move_anon_rmap(old_page, vma);
4138
		set_huge_ptep_writable(vma, haddr, ptep);
N
Nick Piggin 已提交
4139
		return 0;
4140 4141
	}

4142 4143 4144 4145 4146 4147 4148 4149 4150
	/*
	 * 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.
	 */
4151
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4152 4153 4154
			old_page != pagecache_page)
		outside_reserve = 1;

4155
	get_page(old_page);
4156

4157 4158 4159 4160
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
4161
	spin_unlock(ptl);
4162
	new_page = alloc_huge_page(vma, haddr, outside_reserve);
4163

4164
	if (IS_ERR(new_page)) {
4165 4166 4167 4168 4169 4170 4171 4172
		/*
		 * 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) {
4173
			put_page(old_page);
4174
			BUG_ON(huge_pte_none(pte));
4175
			unmap_ref_private(mm, vma, old_page, haddr);
4176 4177
			BUG_ON(huge_pte_none(pte));
			spin_lock(ptl);
4178
			ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4179 4180 4181 4182 4183 4184 4185 4186
			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;
4187 4188
		}

4189
		ret = vmf_error(PTR_ERR(new_page));
4190
		goto out_release_old;
4191 4192
	}

4193 4194 4195 4196
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
4197
	if (unlikely(anon_vma_prepare(vma))) {
4198 4199
		ret = VM_FAULT_OOM;
		goto out_release_all;
4200
	}
4201

4202
	copy_user_huge_page(new_page, old_page, address, vma,
A
Andrea Arcangeli 已提交
4203
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
4204
	__SetPageUptodate(new_page);
4205

4206
	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4207
				haddr + huge_page_size(h));
4208
	mmu_notifier_invalidate_range_start(&range);
4209

4210
	/*
4211
	 * Retake the page table lock to check for racing updates
4212 4213
	 * before the page tables are altered
	 */
4214
	spin_lock(ptl);
4215
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4216
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4217 4218
		ClearPagePrivate(new_page);

4219
		/* Break COW */
4220
		huge_ptep_clear_flush(vma, haddr, ptep);
4221
		mmu_notifier_invalidate_range(mm, range.start, range.end);
4222
		set_huge_pte_at(mm, haddr, ptep,
4223
				make_huge_pte(vma, new_page, 1));
4224
		page_remove_rmap(old_page, true);
4225
		hugepage_add_new_anon_rmap(new_page, vma, haddr);
4226
		set_page_huge_active(new_page);
4227 4228 4229
		/* Make the old page be freed below */
		new_page = old_page;
	}
4230
	spin_unlock(ptl);
4231
	mmu_notifier_invalidate_range_end(&range);
4232
out_release_all:
4233
	restore_reserve_on_error(h, vma, haddr, new_page);
4234
	put_page(new_page);
4235
out_release_old:
4236
	put_page(old_page);
4237

4238 4239
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
4240 4241
}

4242
/* Return the pagecache page at a given address within a VMA */
4243 4244
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
4245 4246
{
	struct address_space *mapping;
4247
	pgoff_t idx;
4248 4249

	mapping = vma->vm_file->f_mapping;
4250
	idx = vma_hugecache_offset(h, vma, address);
4251 4252 4253 4254

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
4255 4256 4257 4258 4259
/*
 * 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
4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272 4273 4274
			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;
}

4275 4276 4277 4278 4279 4280 4281 4282 4283 4284 4285
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);

4286 4287 4288 4289 4290 4291
	/*
	 * set page dirty so that it will not be removed from cache/file
	 * by non-hugetlbfs specific code paths.
	 */
	set_page_dirty(page);

4292 4293 4294 4295 4296 4297
	spin_lock(&inode->i_lock);
	inode->i_blocks += blocks_per_huge_page(h);
	spin_unlock(&inode->i_lock);
	return 0;
}

4298 4299 4300 4301
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)
4302
{
4303
	struct hstate *h = hstate_vma(vma);
4304
	vm_fault_t ret = VM_FAULT_SIGBUS;
4305
	int anon_rmap = 0;
A
Adam Litke 已提交
4306 4307
	unsigned long size;
	struct page *page;
4308
	pte_t new_pte;
4309
	spinlock_t *ptl;
4310
	unsigned long haddr = address & huge_page_mask(h);
4311
	bool new_page = false;
A
Adam Litke 已提交
4312

4313 4314 4315
	/*
	 * 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
4316
	 * COW. Warn that such a situation has occurred as it may not be obvious
4317 4318
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4319
		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4320
			   current->pid);
4321 4322 4323
		return ret;
	}

A
Adam Litke 已提交
4324
	/*
4325 4326 4327
	 * 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
4328
	 */
4329 4330 4331 4332
	size = i_size_read(mapping->host) >> huge_page_shift(h);
	if (idx >= size)
		goto out;

4333 4334 4335
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
4336 4337 4338 4339 4340 4341 4342
		/*
		 * Check for page in userfault range
		 */
		if (userfaultfd_missing(vma)) {
			u32 hash;
			struct vm_fault vmf = {
				.vma = vma,
4343
				.address = haddr,
4344 4345 4346 4347 4348 4349 4350 4351 4352 4353 4354
				.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
				 */
			};

			/*
4355 4356 4357
			 * hugetlb_fault_mutex and i_mmap_rwsem must be
			 * dropped before handling userfault.  Reacquire
			 * after handling fault to make calling code simpler.
4358
			 */
4359
			hash = hugetlb_fault_mutex_hash(mapping, idx);
4360
			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4361
			i_mmap_unlock_read(mapping);
4362
			ret = handle_userfault(&vmf, VM_UFFD_MISSING);
4363
			i_mmap_lock_read(mapping);
4364 4365 4366 4367
			mutex_lock(&hugetlb_fault_mutex_table[hash]);
			goto out;
		}

4368
		page = alloc_huge_page(vma, haddr, 0);
4369
		if (IS_ERR(page)) {
4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380 4381 4382 4383 4384 4385 4386 4387 4388
			/*
			 * 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);
4389
			ret = vmf_error(PTR_ERR(page));
4390 4391
			goto out;
		}
A
Andrea Arcangeli 已提交
4392
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
4393
		__SetPageUptodate(page);
4394
		new_page = true;
4395

4396
		if (vma->vm_flags & VM_MAYSHARE) {
4397
			int err = huge_add_to_page_cache(page, mapping, idx);
4398 4399 4400 4401 4402 4403
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
4404
		} else {
4405
			lock_page(page);
4406 4407 4408 4409
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
4410
			anon_rmap = 1;
4411
		}
4412
	} else {
4413 4414 4415 4416 4417 4418
		/*
		 * 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))) {
4419
			ret = VM_FAULT_HWPOISON |
4420
				VM_FAULT_SET_HINDEX(hstate_index(h));
4421 4422
			goto backout_unlocked;
		}
4423
	}
4424

4425 4426 4427 4428 4429 4430
	/*
	 * 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.
	 */
4431
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4432
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4433 4434 4435
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
4436
		/* Just decrements count, does not deallocate */
4437
		vma_end_reservation(h, vma, haddr);
4438
	}
4439

4440
	ptl = huge_pte_lock(h, mm, ptep);
N
Nick Piggin 已提交
4441
	ret = 0;
4442
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
4443 4444
		goto backout;

4445 4446
	if (anon_rmap) {
		ClearPagePrivate(page);
4447
		hugepage_add_new_anon_rmap(page, vma, haddr);
4448
	} else
4449
		page_dup_rmap(page, true);
4450 4451
	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
				&& (vma->vm_flags & VM_SHARED)));
4452
	set_huge_pte_at(mm, haddr, ptep, new_pte);
4453

4454
	hugetlb_count_add(pages_per_huge_page(h), mm);
4455
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4456
		/* Optimization, do the COW without a second fault */
4457
		ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4458 4459
	}

4460
	spin_unlock(ptl);
4461 4462 4463 4464 4465 4466 4467 4468 4469

	/*
	 * 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
4470 4471
	unlock_page(page);
out:
4472
	return ret;
A
Adam Litke 已提交
4473 4474

backout:
4475
	spin_unlock(ptl);
4476
backout_unlocked:
A
Adam Litke 已提交
4477
	unlock_page(page);
4478
	restore_reserve_on_error(h, vma, haddr, page);
A
Adam Litke 已提交
4479 4480
	put_page(page);
	goto out;
4481 4482
}

4483
#ifdef CONFIG_SMP
4484
u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4485 4486 4487 4488
{
	unsigned long key[2];
	u32 hash;

4489 4490
	key[0] = (unsigned long) mapping;
	key[1] = idx;
4491

4492
	hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4493 4494 4495 4496 4497 4498 4499 4500

	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.
 */
4501
u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4502 4503 4504 4505 4506
{
	return 0;
}
#endif

4507
vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4508
			unsigned long address, unsigned int flags)
4509
{
4510
	pte_t *ptep, entry;
4511
	spinlock_t *ptl;
4512
	vm_fault_t ret;
4513 4514
	u32 hash;
	pgoff_t idx;
4515
	struct page *page = NULL;
4516
	struct page *pagecache_page = NULL;
4517
	struct hstate *h = hstate_vma(vma);
4518
	struct address_space *mapping;
4519
	int need_wait_lock = 0;
4520
	unsigned long haddr = address & huge_page_mask(h);
4521

4522
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4523
	if (ptep) {
4524 4525 4526 4527 4528
		/*
		 * 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.
		 */
4529
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
4530
		if (unlikely(is_hugetlb_entry_migration(entry))) {
4531
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
4532 4533
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4534
			return VM_FAULT_HWPOISON_LARGE |
4535
				VM_FAULT_SET_HINDEX(hstate_index(h));
4536 4537 4538 4539
	} else {
		ptep = huge_pte_alloc(mm, haddr, huge_page_size(h));
		if (!ptep)
			return VM_FAULT_OOM;
4540 4541
	}

4542 4543
	/*
	 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4544 4545 4546 4547
	 * 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.
4548 4549 4550 4551 4552
	 *
	 * 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.
	 */
4553
	mapping = vma->vm_file->f_mapping;
4554 4555 4556 4557 4558 4559
	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;
	}
4560

4561 4562 4563 4564 4565
	/*
	 * 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.
	 */
4566
	idx = vma_hugecache_offset(h, vma, haddr);
4567
	hash = hugetlb_fault_mutex_hash(mapping, idx);
4568
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
4569

4570 4571
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
4572
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4573
		goto out_mutex;
4574
	}
4575

N
Nick Piggin 已提交
4576
	ret = 0;
4577

4578 4579 4580
	/*
	 * 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
4581 4582 4583
	 * an active hugepage in pagecache. This goto expects the 2nd page
	 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
	 * properly handle it.
4584 4585 4586 4587
	 */
	if (!pte_present(entry))
		goto out_mutex;

4588 4589 4590 4591 4592 4593 4594 4595
	/*
	 * 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.
	 */
4596
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4597
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4598
			ret = VM_FAULT_OOM;
4599
			goto out_mutex;
4600
		}
4601
		/* Just decrements count, does not deallocate */
4602
		vma_end_reservation(h, vma, haddr);
4603

4604
		if (!(vma->vm_flags & VM_MAYSHARE))
4605
			pagecache_page = hugetlbfs_pagecache_page(h,
4606
								vma, haddr);
4607 4608
	}

4609 4610 4611 4612 4613 4614
	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;

4615 4616 4617 4618 4619 4620 4621
	/*
	 * 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)
4622 4623 4624 4625
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
4626

4627
	get_page(page);
4628

4629
	if (flags & FAULT_FLAG_WRITE) {
4630
		if (!huge_pte_write(entry)) {
4631
			ret = hugetlb_cow(mm, vma, address, ptep,
4632
					  pagecache_page, ptl);
4633
			goto out_put_page;
4634
		}
4635
		entry = huge_pte_mkdirty(entry);
4636 4637
	}
	entry = pte_mkyoung(entry);
4638
	if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4639
						flags & FAULT_FLAG_WRITE))
4640
		update_mmu_cache(vma, haddr, ptep);
4641 4642 4643 4644
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
4645 4646
out_ptl:
	spin_unlock(ptl);
4647 4648 4649 4650 4651

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
4652
out_mutex:
4653
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4654
	i_mmap_unlock_read(mapping);
4655 4656 4657 4658 4659 4660 4661 4662 4663
	/*
	 * 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);
4664
	return ret;
4665 4666
}

4667 4668 4669 4670 4671 4672 4673 4674 4675 4676 4677
/*
 * 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)
{
4678 4679 4680
	struct address_space *mapping;
	pgoff_t idx;
	unsigned long size;
4681
	int vm_shared = dst_vma->vm_flags & VM_SHARED;
4682 4683 4684 4685 4686 4687 4688 4689 4690 4691 4692 4693 4694 4695
	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,
4696
						pages_per_huge_page(h), false);
4697 4698 4699

		/* fallback to copy_from_user outside mmap_sem */
		if (unlikely(ret)) {
4700
			ret = -ENOENT;
4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715 4716
			*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);

4717 4718 4719
	mapping = dst_vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, dst_vma, dst_addr);

4720 4721 4722 4723
	/*
	 * If shared, add to page cache
	 */
	if (vm_shared) {
4724 4725 4726 4727
		size = i_size_read(mapping->host) >> huge_page_shift(h);
		ret = -EFAULT;
		if (idx >= size)
			goto out_release_nounlock;
4728

4729 4730 4731 4732 4733 4734
		/*
		 * 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.
		 */
4735 4736 4737 4738 4739
		ret = huge_add_to_page_cache(page, mapping, idx);
		if (ret)
			goto out_release_nounlock;
	}

4740 4741 4742
	ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
	spin_lock(ptl);

4743 4744 4745 4746 4747 4748 4749 4750 4751 4752 4753 4754 4755 4756
	/*
	 * 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;

4757 4758 4759 4760
	ret = -EEXIST;
	if (!huge_pte_none(huge_ptep_get(dst_pte)))
		goto out_release_unlock;

4761 4762 4763 4764 4765 4766
	if (vm_shared) {
		page_dup_rmap(page, true);
	} else {
		ClearPagePrivate(page);
		hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
	}
4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778 4779 4780 4781 4782

	_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);
4783
	set_page_huge_active(page);
4784 4785
	if (vm_shared)
		unlock_page(page);
4786 4787 4788 4789 4790
	ret = 0;
out:
	return ret;
out_release_unlock:
	spin_unlock(ptl);
4791 4792
	if (vm_shared)
		unlock_page(page);
4793
out_release_nounlock:
4794 4795 4796 4797
	put_page(page);
	goto out;
}

4798 4799 4800
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,
4801
			 long i, unsigned int flags, int *locked)
D
David Gibson 已提交
4802
{
4803 4804
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
4805
	unsigned long remainder = *nr_pages;
4806
	struct hstate *h = hstate_vma(vma);
4807
	int err = -EFAULT;
D
David Gibson 已提交
4808 4809

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
4810
		pte_t *pte;
4811
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
4812
		int absent;
A
Adam Litke 已提交
4813
		struct page *page;
D
David Gibson 已提交
4814

4815 4816 4817 4818
		/*
		 * If we have a pending SIGKILL, don't keep faulting pages and
		 * potentially allocating memory.
		 */
4819
		if (fatal_signal_pending(current)) {
4820 4821 4822 4823
			remainder = 0;
			break;
		}

A
Adam Litke 已提交
4824 4825
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
4826
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
4827
		 * first, for the page indexing below to work.
4828 4829
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
4830
		 */
4831 4832
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
				      huge_page_size(h));
4833 4834
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
4835 4836 4837 4838
		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
4839 4840 4841 4842
		 * 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
4843
		 */
H
Hugh Dickins 已提交
4844 4845
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4846 4847
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
4848 4849 4850
			remainder = 0;
			break;
		}
D
David Gibson 已提交
4851

4852 4853 4854 4855 4856 4857 4858 4859 4860 4861 4862
		/*
		 * 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)) ||
4863 4864
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
4865
			vm_fault_t ret;
4866
			unsigned int fault_flags = 0;
D
David Gibson 已提交
4867

4868 4869
			if (pte)
				spin_unlock(ptl);
4870 4871
			if (flags & FOLL_WRITE)
				fault_flags |= FAULT_FLAG_WRITE;
4872
			if (locked)
4873 4874
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_KILLABLE;
4875 4876 4877 4878
			if (flags & FOLL_NOWAIT)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_RETRY_NOWAIT;
			if (flags & FOLL_TRIED) {
4879 4880 4881 4882
				/*
				 * Note: FAULT_FLAG_ALLOW_RETRY and
				 * FAULT_FLAG_TRIED can co-exist
				 */
4883 4884 4885 4886
				fault_flags |= FAULT_FLAG_TRIED;
			}
			ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
			if (ret & VM_FAULT_ERROR) {
4887
				err = vm_fault_to_errno(ret, flags);
4888 4889 4890 4891
				remainder = 0;
				break;
			}
			if (ret & VM_FAULT_RETRY) {
4892
				if (locked &&
4893
				    !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4894
					*locked = 0;
4895 4896 4897 4898 4899 4900 4901 4902 4903 4904 4905 4906 4907
				*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
4908 4909
		}

4910
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4911
		page = pte_page(huge_ptep_get(pte));
4912

4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926
		/*
		 * 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;
		}

4927
same_page:
4928
		if (pages) {
H
Hugh Dickins 已提交
4929
			pages[i] = mem_map_offset(page, pfn_offset);
J
John Hubbard 已提交
4930 4931 4932 4933 4934 4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 4945
			/*
			 * 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;
			}
4946
		}
D
David Gibson 已提交
4947 4948 4949 4950 4951

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
4952
		++pfn_offset;
D
David Gibson 已提交
4953 4954
		--remainder;
		++i;
4955
		if (vaddr < vma->vm_end && remainder &&
4956
				pfn_offset < pages_per_huge_page(h)) {
4957 4958 4959 4960 4961 4962
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
4963
		spin_unlock(ptl);
D
David Gibson 已提交
4964
	}
4965
	*nr_pages = remainder;
4966 4967 4968 4969 4970
	/*
	 * 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
4971 4972
	*position = vaddr;

4973
	return i ? i : err;
D
David Gibson 已提交
4974
}
4975

4976 4977 4978 4979 4980 4981 4982 4983
#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

4984
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4985 4986 4987 4988 4989 4990
		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;
4991
	struct hstate *h = hstate_vma(vma);
4992
	unsigned long pages = 0;
4993
	bool shared_pmd = false;
4994
	struct mmu_notifier_range range;
4995 4996 4997

	/*
	 * In the case of shared PMDs, the area to flush could be beyond
4998
	 * start/end.  Set range.start/range.end to cover the maximum possible
4999 5000
	 * range if PMD sharing is possible.
	 */
5001 5002
	mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
				0, vma, mm, start, end);
5003
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5004 5005

	BUG_ON(address >= end);
5006
	flush_cache_range(vma, range.start, range.end);
5007

5008
	mmu_notifier_invalidate_range_start(&range);
5009
	i_mmap_lock_write(vma->vm_file->f_mapping);
5010
	for (; address < end; address += huge_page_size(h)) {
5011
		spinlock_t *ptl;
5012
		ptep = huge_pte_offset(mm, address, huge_page_size(h));
5013 5014
		if (!ptep)
			continue;
5015
		ptl = huge_pte_lock(h, mm, ptep);
5016 5017
		if (huge_pmd_unshare(mm, &address, ptep)) {
			pages++;
5018
			spin_unlock(ptl);
5019
			shared_pmd = true;
5020
			continue;
5021
		}
5022 5023 5024 5025 5026 5027 5028 5029 5030 5031 5032 5033 5034
		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);
5035 5036
				set_huge_swap_pte_at(mm, address, ptep,
						     newpte, huge_page_size(h));
5037 5038 5039 5040 5041 5042
				pages++;
			}
			spin_unlock(ptl);
			continue;
		}
		if (!huge_pte_none(pte)) {
5043 5044 5045 5046
			pte_t old_pte;

			old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
			pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5047
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
5048
			huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5049
			pages++;
5050
		}
5051
		spin_unlock(ptl);
5052
	}
5053
	/*
5054
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5055
	 * may have cleared our pud entry and done put_page on the page table:
5056
	 * once we release i_mmap_rwsem, another task can do the final put_page
5057 5058
	 * 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.
5059
	 */
5060
	if (shared_pmd)
5061
		flush_hugetlb_tlb_range(vma, range.start, range.end);
5062 5063
	else
		flush_hugetlb_tlb_range(vma, start, end);
5064 5065 5066 5067
	/*
	 * No need to call mmu_notifier_invalidate_range() we are downgrading
	 * page table protection not changing it to point to a new page.
	 *
5068
	 * See Documentation/vm/mmu_notifier.rst
5069
	 */
5070
	i_mmap_unlock_write(vma->vm_file->f_mapping);
5071
	mmu_notifier_invalidate_range_end(&range);
5072 5073

	return pages << h->order;
5074 5075
}

5076 5077
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
5078
					struct vm_area_struct *vma,
5079
					vm_flags_t vm_flags)
5080
{
5081
	long ret, chg, add = -1;
5082
	struct hstate *h = hstate_inode(inode);
5083
	struct hugepage_subpool *spool = subpool_inode(inode);
5084
	struct resv_map *resv_map;
5085
	struct hugetlb_cgroup *h_cg = NULL;
5086
	long gbl_reserve, regions_needed = 0;
5087

5088 5089 5090 5091 5092 5093
	/* This should never happen */
	if (from > to) {
		VM_WARN(1, "%s called with a negative range\n", __func__);
		return -EINVAL;
	}

5094 5095 5096
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
5097
	 * without using reserves
5098
	 */
5099
	if (vm_flags & VM_NORESERVE)
5100 5101
		return 0;

5102 5103 5104 5105 5106 5107
	/*
	 * 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
	 */
5108
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
5109 5110 5111 5112 5113
		/*
		 * 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).
		 */
5114
		resv_map = inode_resv_map(inode);
5115

5116
		chg = region_chg(resv_map, from, to, &regions_needed);
5117 5118

	} else {
5119
		/* Private mapping. */
5120
		resv_map = resv_map_alloc();
5121 5122 5123
		if (!resv_map)
			return -ENOMEM;

5124
		chg = to - from;
5125

5126 5127 5128 5129
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

5130 5131 5132 5133
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
5134

5135 5136 5137 5138 5139 5140 5141 5142 5143 5144 5145 5146 5147 5148 5149
	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);
	}

5150 5151 5152 5153 5154 5155 5156
	/*
	 * 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) {
5157
		ret = -ENOSPC;
5158
		goto out_uncharge_cgroup;
5159
	}
5160 5161

	/*
5162
	 * Check enough hugepages are available for the reservation.
5163
	 * Hand the pages back to the subpool if there are not
5164
	 */
5165
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
5166
	if (ret < 0) {
5167
		goto out_put_pages;
K
Ken Chen 已提交
5168
	}
5169 5170 5171 5172 5173 5174 5175 5176 5177 5178 5179 5180

	/*
	 * 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
	 */
5181
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
5182
		add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5183 5184 5185

		if (unlikely(add < 0)) {
			hugetlb_acct_memory(h, -gbl_reserve);
5186
			goto out_put_pages;
5187
		} else if (unlikely(chg > add)) {
5188 5189 5190 5191 5192 5193 5194 5195 5196
			/*
			 * 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;

5197 5198 5199 5200
			hugetlb_cgroup_uncharge_cgroup_rsvd(
				hstate_index(h),
				(chg - add) * pages_per_huge_page(h), h_cg);

5201 5202 5203 5204 5205
			rsv_adjust = hugepage_subpool_put_pages(spool,
								chg - add);
			hugetlb_acct_memory(h, -rsv_adjust);
		}
	}
5206
	return 0;
5207 5208 5209 5210 5211 5212
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);
5213
out_err:
5214
	if (!vma || vma->vm_flags & VM_MAYSHARE)
5215 5216 5217 5218 5219
		/* 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
5220 5221
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
5222
	return ret;
5223 5224
}

5225 5226
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
5227
{
5228
	struct hstate *h = hstate_inode(inode);
5229
	struct resv_map *resv_map = inode_resv_map(inode);
5230
	long chg = 0;
5231
	struct hugepage_subpool *spool = subpool_inode(inode);
5232
	long gbl_reserve;
K
Ken Chen 已提交
5233

5234 5235 5236 5237
	/*
	 * Since this routine can be called in the evict inode path for all
	 * hugetlbfs inodes, resv_map could be NULL.
	 */
5238 5239 5240 5241 5242 5243 5244 5245 5246 5247 5248
	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
5249
	spin_lock(&inode->i_lock);
5250
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
5251 5252
	spin_unlock(&inode->i_lock);

5253 5254 5255 5256 5257 5258
	/*
	 * 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);
5259 5260

	return 0;
5261
}
5262

5263 5264 5265 5266 5267 5268 5269 5270 5271 5272 5273
#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
5274 5275
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5276 5277 5278 5279 5280 5281 5282 5283 5284 5285 5286 5287 5288

	/*
	 * 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;
}

5289
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5290 5291 5292 5293 5294 5295 5296
{
	unsigned long base = addr & PUD_MASK;
	unsigned long end = base + PUD_SIZE;

	/*
	 * check on proper vm_flags and page table alignment
	 */
5297
	if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5298 5299
		return true;
	return false;
5300 5301
}

5302 5303 5304 5305 5306 5307 5308 5309
/*
 * 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)
{
5310
	unsigned long check_addr;
5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330

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

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

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

5331 5332 5333 5334
/*
 * 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
5335 5336 5337 5338 5339 5340
 * code much cleaner.
 *
 * This routine must be called with i_mmap_rwsem held in at least read mode.
 * 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).
5341 5342 5343 5344 5345 5346 5347 5348 5349 5350 5351
 */
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;
5352
	spinlock_t *ptl;
5353 5354 5355 5356 5357 5358 5359 5360 5361 5362

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

	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

		saddr = page_table_shareable(svma, vma, addr, idx);
		if (saddr) {
5363 5364
			spte = huge_pte_offset(svma->vm_mm, saddr,
					       vma_mmu_pagesize(svma));
5365 5366 5367 5368 5369 5370 5371 5372 5373 5374
			if (spte) {
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

5375
	ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5376
	if (pud_none(*pud)) {
5377 5378
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
5379
		mm_inc_nr_pmds(mm);
5380
	} else {
5381
		put_page(virt_to_page(spte));
5382
	}
5383
	spin_unlock(ptl);
5384 5385 5386 5387 5388 5389 5390 5391 5392 5393 5394 5395
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.
 *
5396
 * Called with page table lock held and i_mmap_rwsem held in write mode.
5397 5398 5399 5400 5401 5402 5403
 *
 * returns: 1 successfully unmapped a shared pte page
 *	    0 the underlying pte page is not shared, or it is the last user
 */
int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	pgd_t *pgd = pgd_offset(mm, *addr);
5404 5405
	p4d_t *p4d = p4d_offset(pgd, *addr);
	pud_t *pud = pud_offset(p4d, *addr);
5406 5407 5408 5409 5410 5411 5412

	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));
5413
	mm_dec_nr_pmds(mm);
5414 5415 5416
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
5417 5418 5419 5420 5421 5422
#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;
}
5423 5424 5425 5426 5427

int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
{
	return 0;
}
5428 5429 5430 5431 5432

void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
				unsigned long *start, unsigned long *end)
{
}
5433
#define want_pmd_share()	(0)
5434 5435
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

5436 5437 5438 5439 5440
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
5441
	p4d_t *p4d;
5442 5443 5444 5445
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
5446 5447 5448
	p4d = p4d_alloc(mm, pgd, addr);
	if (!p4d)
		return NULL;
5449
	pud = pud_alloc(mm, p4d, addr);
5450 5451 5452 5453 5454 5455 5456 5457 5458 5459 5460
	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);
		}
	}
5461
	BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5462 5463 5464 5465

	return pte;
}

5466 5467 5468 5469
/*
 * huge_pte_offset() - Walk the page table to resolve the hugepage
 * entry at address @addr
 *
5470 5471
 * Return: Pointer to page table entry (PUD or PMD) for
 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5472 5473 5474
 * size @sz doesn't match the hugepage size at this level of the page
 * table.
 */
5475 5476
pte_t *huge_pte_offset(struct mm_struct *mm,
		       unsigned long addr, unsigned long sz)
5477 5478
{
	pgd_t *pgd;
5479
	p4d_t *p4d;
5480 5481
	pud_t *pud;
	pmd_t *pmd;
5482 5483

	pgd = pgd_offset(mm, addr);
5484 5485 5486 5487 5488
	if (!pgd_present(*pgd))
		return NULL;
	p4d = p4d_offset(pgd, addr);
	if (!p4d_present(*p4d))
		return NULL;
5489

5490
	pud = pud_offset(p4d, addr);
5491 5492
	if (sz == PUD_SIZE)
		/* must be pud huge, non-present or none */
5493
		return (pte_t *)pud;
5494
	if (!pud_present(*pud))
5495
		return NULL;
5496
	/* must have a valid entry and size to go further */
5497

5498 5499 5500
	pmd = pmd_offset(pud, addr);
	/* must be pmd huge, non-present or none */
	return (pte_t *)pmd;
5501 5502
}

5503 5504 5505 5506 5507 5508 5509 5510 5511 5512 5513 5514 5515
#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);
}

5516 5517 5518 5519 5520 5521 5522 5523
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;
}

5524
struct page * __weak
5525
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5526
		pmd_t *pmd, int flags)
5527
{
5528 5529
	struct page *page = NULL;
	spinlock_t *ptl;
5530
	pte_t pte;
J
John Hubbard 已提交
5531 5532 5533 5534 5535 5536

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

5537 5538 5539 5540 5541 5542 5543 5544 5545
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;
5546 5547
	pte = huge_ptep_get((pte_t *)pmd);
	if (pte_present(pte)) {
5548
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
J
John Hubbard 已提交
5549 5550 5551 5552 5553 5554 5555 5556 5557 5558 5559 5560
		/*
		 * 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;
		}
5561
	} else {
5562
		if (is_hugetlb_entry_migration(pte)) {
5563 5564 5565 5566 5567 5568 5569 5570 5571 5572 5573
			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);
5574 5575 5576
	return page;
}

5577
struct page * __weak
5578
follow_huge_pud(struct mm_struct *mm, unsigned long address,
5579
		pud_t *pud, int flags)
5580
{
J
John Hubbard 已提交
5581
	if (flags & (FOLL_GET | FOLL_PIN))
5582
		return NULL;
5583

5584
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5585 5586
}

5587 5588 5589
struct page * __weak
follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
{
J
John Hubbard 已提交
5590
	if (flags & (FOLL_GET | FOLL_PIN))
5591 5592 5593 5594 5595
		return NULL;

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

5596 5597
bool isolate_huge_page(struct page *page, struct list_head *list)
{
5598 5599
	bool ret = true;

5600
	VM_BUG_ON_PAGE(!PageHead(page), page);
5601
	spin_lock(&hugetlb_lock);
5602 5603 5604 5605 5606
	if (!page_huge_active(page) || !get_page_unless_zero(page)) {
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
5607
	list_move_tail(&page->lru, list);
5608
unlock:
5609
	spin_unlock(&hugetlb_lock);
5610
	return ret;
5611 5612 5613 5614
}

void putback_active_hugepage(struct page *page)
{
5615
	VM_BUG_ON_PAGE(!PageHead(page), page);
5616
	spin_lock(&hugetlb_lock);
5617
	set_page_huge_active(page);
5618 5619 5620 5621
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}
5622 5623 5624 5625 5626 5627 5628 5629 5630 5631 5632 5633 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643 5644 5645 5646 5647 5648 5649 5650 5651 5652 5653 5654

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);
	}
}
5655 5656 5657 5658 5659 5660 5661 5662 5663 5664 5665 5666 5667 5668 5669 5670 5671 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 5711 5712 5713 5714 5715 5716 5717 5718 5719 5720 5721 5722 5723 5724 5725

#ifdef CONFIG_CMA
static unsigned long hugetlb_cma_size __initdata;
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;

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

		res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
						 0, false, "hugetlb",
						 &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 */