hugetlb.c 157.5 KB
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// SPDX-License-Identifier: GPL-2.0-only
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/*
 * Generic hugetlb support.
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 * (C) Nadia Yvette Chambers, April 2004
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 */
#include <linux/list.h>
#include <linux/init.h>
#include <linux/mm.h>
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#include <linux/seq_file.h>
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#include <linux/sysctl.h>
#include <linux/highmem.h>
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#include <linux/mmu_notifier.h>
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#include <linux/nodemask.h>
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#include <linux/pagemap.h>
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#include <linux/mempolicy.h>
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#include <linux/compiler.h>
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#include <linux/cpuset.h>
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#include <linux/mutex.h>
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#include <linux/memblock.h>
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#include <linux/sysfs.h>
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#include <linux/slab.h>
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#include <linux/sched/mm.h>
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#include <linux/mmdebug.h>
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#include <linux/sched/signal.h>
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#include <linux/rmap.h>
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#include <linux/string_helpers.h>
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#include <linux/swap.h>
#include <linux/swapops.h>
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#include <linux/jhash.h>
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#include <linux/numa.h>
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#include <linux/llist.h>
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#include <linux/cma.h>
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#include <asm/page.h>
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#include <asm/pgalloc.h>
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#include <asm/tlb.h>
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#include <linux/io.h>
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#include <linux/hugetlb.h>
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#include <linux/hugetlb_cgroup.h>
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#include <linux/node.h>
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#include <linux/userfaultfd_k.h>
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#include <linux/page_owner.h>
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#include "internal.h"
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int hugetlb_max_hstate __read_mostly;
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unsigned int default_hstate_idx;
struct hstate hstates[HUGE_MAX_HSTATE];
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#ifdef CONFIG_CMA
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static struct cma *hugetlb_cma[MAX_NUMNODES];
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#endif
static unsigned long hugetlb_cma_size __initdata;
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/*
 * Minimum page order among possible hugepage sizes, set to a proper value
 * at boot time.
 */
static unsigned int minimum_order __read_mostly = UINT_MAX;
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__initdata LIST_HEAD(huge_boot_pages);

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/* for command line parsing */
static struct hstate * __initdata parsed_hstate;
static unsigned long __initdata default_hstate_max_huge_pages;
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static bool __initdata parsed_valid_hugepagesz = true;
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static bool __initdata parsed_default_hugepagesz;
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/*
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 * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
 * free_huge_pages, and surplus_huge_pages.
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 */
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DEFINE_SPINLOCK(hugetlb_lock);
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/*
 * Serializes faults on the same logical page.  This is used to
 * prevent spurious OOMs when the hugepage pool is fully utilized.
 */
static int num_fault_mutexes;
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struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
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static inline bool PageHugeFreed(struct page *head)
{
	return page_private(head + 4) == -1UL;
}

static inline void SetPageHugeFreed(struct page *head)
{
	set_page_private(head + 4, -1UL);
}

static inline void ClearPageHugeFreed(struct page *head)
{
	set_page_private(head + 4, 0);
}

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/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);

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

	spin_unlock(&spool->lock);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	VM_BUG_ON(resv->region_cache_count <= 0);

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

	nrg->from = from;
	nrg->to = to;

	return nrg;
}

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

/* Helper that records hugetlb_cgroup uncharge info. */
static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
						struct hstate *h,
						struct resv_map *resv,
						struct file_region *nrg)
{
#ifdef CONFIG_CGROUP_HUGETLB
	if (h_cg) {
		nrg->reservation_counter =
			&h_cg->rsvd_hugepage[hstate_index(h)];
		nrg->css = &h_cg->css;
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		/*
		 * The caller will hold exactly one h_cg->css reference for the
		 * whole contiguous reservation region. But this area might be
		 * scattered when there are already some file_regions reside in
		 * it. As a result, many file_regions may share only one css
		 * reference. In order to ensure that one file_region must hold
		 * exactly one h_cg->css reference, we should do css_get for
		 * each file_region and leave the reference held by caller
		 * untouched.
		 */
		css_get(&h_cg->css);
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		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 void put_uncharge_info(struct file_region *rg)
{
#ifdef CONFIG_CGROUP_HUGETLB
	if (rg->css)
		css_put(rg->css);
#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);
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		put_uncharge_info(rg);
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		kfree(rg);

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		rg = prg;
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	}

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

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

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

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

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

		last_accounted_offset = rg->to;
	}

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

	VM_BUG_ON(add < 0);
	return add;
}

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

	VM_BUG_ON(regions_needed < 0);

	INIT_LIST_HEAD(&allocated_regions);

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

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

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

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		spin_lock(&resv->lock);

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

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

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

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

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	add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
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	resv->adds_in_progress -= in_regions_needed;
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	spin_unlock(&resv->lock);
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	VM_BUG_ON(add < 0);
	return add;
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}

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/*
 * Examine the existing reserve map and determine how many
 * huge pages in the specified range [f, t) are NOT currently
 * represented.  This routine is called before a subsequent
 * call to region_add that will actually modify the reserve
 * map to add the specified range [f, t).  region_chg does
 * not change the number of huge pages represented by the
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 * map.  A number of new file_region structures is added to the cache as a
 * placeholder, for the subsequent region_add call to use. At least 1
 * file_region structure is added.
 *
 * out_regions_needed is the number of regions added to the
 * resv->adds_in_progress.  This value needs to be provided to a follow up call
 * to region_add or region_abort for proper accounting.
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 *
 * Returns the number of huge pages that need to be added to the existing
 * reservation map for the range [f, t).  This number is greater or equal to
 * zero.  -ENOMEM is returned if a new file_region structure or cache entry
 * is needed and can not be allocated.
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 */
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static long region_chg(struct resv_map *resv, long f, long t,
		       long *out_regions_needed)
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{
	long chg = 0;

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	spin_lock(&resv->lock);
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	/* Count how many hugepages in this range are NOT represented. */
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	chg = add_reservation_in_range(resv, f, t, NULL, NULL,
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				       out_regions_needed);
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	if (*out_regions_needed == 0)
		*out_regions_needed = 1;
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	if (allocate_file_region_entries(resv, *out_regions_needed))
		return -ENOMEM;
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	resv->adds_in_progress += *out_regions_needed;
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	spin_unlock(&resv->lock);
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	return chg;
}

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

627
/*
628 629 630 631 632 633 634 635 636 637 638 639
 * 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.
640
 */
641
static long region_del(struct resv_map *resv, long f, long t)
642
{
643
	struct list_head *head = &resv->regions;
644
	struct file_region *rg, *trg;
645 646
	struct file_region *nrg = NULL;
	long del = 0;
647

648
retry:
649
	spin_lock(&resv->lock);
650
	list_for_each_entry_safe(rg, trg, head, link) {
651 652 653 654 655 656 657 658
		/*
		 * 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))
659
			continue;
660

661
		if (rg->from >= t)
662 663
			break;

664 665 666 667 668 669 670 671 672 673 674 675 676
		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--;
			}
677

678 679 680 681 682 683 684 685 686
			if (!nrg) {
				spin_unlock(&resv->lock);
				nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
				if (!nrg)
					return -ENOMEM;
				goto retry;
			}

			del += t - f;
687
			hugetlb_cgroup_uncharge_file_region(
688
				resv, rg, t - f, false);
689 690 691 692

			/* New entry for end of split region */
			nrg->from = t;
			nrg->to = rg->to;
693 694 695

			copy_hugetlb_cgroup_uncharge_info(nrg, rg);

696 697 698 699 700 701 702
			INIT_LIST_HEAD(&nrg->link);

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

			list_add(&nrg->link, &rg->link);
			nrg = NULL;
703
			break;
704 705 706 707
		}

		if (f <= rg->from && t >= rg->to) { /* Remove entire region */
			del += rg->to - rg->from;
708
			hugetlb_cgroup_uncharge_file_region(resv, rg,
709
							    rg->to - rg->from, true);
710 711 712 713 714 715
			list_del(&rg->link);
			kfree(rg);
			continue;
		}

		if (f <= rg->from) {	/* Trim beginning of region */
716
			hugetlb_cgroup_uncharge_file_region(resv, rg,
717
							    t - rg->from, false);
718

719 720 721
			del += t - rg->from;
			rg->from = t;
		} else {		/* Trim end of region */
722
			hugetlb_cgroup_uncharge_file_region(resv, rg,
723
							    rg->to - f, false);
724 725 726

			del += rg->to - f;
			rg->to = f;
727
		}
728
	}
729 730

	spin_unlock(&resv->lock);
731 732
	kfree(nrg);
	return del;
733 734
}

735 736 737 738 739 740 741 742 743
/*
 * 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.
 */
744
void hugetlb_fix_reserve_counts(struct inode *inode)
745 746 747
{
	struct hugepage_subpool *spool = subpool_inode(inode);
	long rsv_adjust;
748
	bool reserved = false;
749 750

	rsv_adjust = hugepage_subpool_get_pages(spool, 1);
751
	if (rsv_adjust > 0) {
752 753
		struct hstate *h = hstate_inode(inode);

754 755 756 757
		if (!hugetlb_acct_memory(h, 1))
			reserved = true;
	} else if (!rsv_adjust) {
		reserved = true;
758
	}
759 760 761

	if (!reserved)
		pr_warn("hugetlb: Huge Page Reserved count may go negative.\n");
762 763
}

764 765 766 767
/*
 * Count and return the number of huge pages in the reserve map
 * that intersect with the range [f, t).
 */
768
static long region_count(struct resv_map *resv, long f, long t)
769
{
770
	struct list_head *head = &resv->regions;
771 772 773
	struct file_region *rg;
	long chg = 0;

774
	spin_lock(&resv->lock);
775 776
	/* Locate each segment we overlap with, and count that overlap. */
	list_for_each_entry(rg, head, link) {
777 778
		long seg_from;
		long seg_to;
779 780 781 782 783 784 785 786 787 788 789

		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;
	}
790
	spin_unlock(&resv->lock);
791 792 793 794

	return chg;
}

795 796 797 798
/*
 * Convert the address within this vma to the page offset within
 * the mapping, in pagecache page units; huge pages here.
 */
799 800
static pgoff_t vma_hugecache_offset(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
801
{
802 803
	return ((address - vma->vm_start) >> huge_page_shift(h)) +
			(vma->vm_pgoff >> huge_page_order(h));
804 805
}

806 807 808 809 810
pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
				     unsigned long address)
{
	return vma_hugecache_offset(hstate_vma(vma), vma, address);
}
811
EXPORT_SYMBOL_GPL(linear_hugepage_index);
812

813 814 815 816 817 818
/*
 * 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)
{
819 820 821
	if (vma->vm_ops && vma->vm_ops->pagesize)
		return vma->vm_ops->pagesize(vma);
	return PAGE_SIZE;
822
}
823
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
824

825 826 827
/*
 * 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
828 829
 * architectures where it differs, an architecture-specific 'strong'
 * version of this symbol is required.
830
 */
831
__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
832 833 834 835
{
	return vma_kernel_pagesize(vma);
}

836 837 838 839 840 841 842
/*
 * 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)
843
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
844

845 846 847 848 849 850 851 852 853
/*
 * 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.
854 855 856 857 858 859 860 861 862
 *
 * 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.
863
 */
864 865 866 867 868 869 870 871 872 873 874
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;
}

875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893
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
}

894
struct resv_map *resv_map_alloc(void)
895 896
{
	struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
897 898 899 900 901
	struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);

	if (!resv_map || !rg) {
		kfree(resv_map);
		kfree(rg);
902
		return NULL;
903
	}
904 905

	kref_init(&resv_map->refs);
906
	spin_lock_init(&resv_map->lock);
907 908
	INIT_LIST_HEAD(&resv_map->regions);

909
	resv_map->adds_in_progress = 0;
910 911 912 913 914 915 916
	/*
	 * 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);
917 918 919 920 921

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

922 923 924
	return resv_map;
}

925
void resv_map_release(struct kref *ref)
926 927
{
	struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
928 929
	struct list_head *head = &resv_map->region_cache;
	struct file_region *rg, *trg;
930 931

	/* Clear out any active regions before we release the map. */
932
	region_del(resv_map, 0, LONG_MAX);
933 934 935 936 937 938 939 940 941

	/* ... 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);

942 943 944
	kfree(resv_map);
}

945 946
static inline struct resv_map *inode_resv_map(struct inode *inode)
{
947 948 949 950 951 952 953 954 955
	/*
	 * 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;
956 957
}

958
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
959
{
960
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
961 962 963 964 965 966 967
	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 {
968 969
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
970
	}
971 972
}

973
static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
974
{
975 976
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
977

978 979
	set_vma_private_data(vma, (get_vma_private_data(vma) &
				HPAGE_RESV_MASK) | (unsigned long)map);
980 981 982 983
}

static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
{
984 985
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
	VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
986 987

	set_vma_private_data(vma, get_vma_private_data(vma) | flags);
988 989 990 991
}

static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
{
992
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
993 994

	return (get_vma_private_data(vma) & flag) != 0;
995 996
}

997
/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
998 999
void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
{
1000
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
1001
	if (!(vma->vm_flags & VM_MAYSHARE))
1002 1003 1004 1005
		vma->vm_private_data = (void *)0;
}

/* Returns true if the VMA has associated reserve pages */
1006
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
1007
{
1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018
	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)
1019
			return true;
1020
		else
1021
			return false;
1022
	}
1023 1024

	/* Shared mappings always use reserves */
1025 1026 1027 1028 1029
	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
1030
		 * fallocate.  In this case, there really are no reserves to
1031 1032 1033 1034 1035 1036 1037
		 * use.  This situation is indicated if chg != 0.
		 */
		if (chg)
			return false;
		else
			return true;
	}
1038 1039 1040 1041 1042

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063
	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;
	}
1064

1065
	return false;
1066 1067
}

1068
static void enqueue_huge_page(struct hstate *h, struct page *page)
L
Linus Torvalds 已提交
1069 1070
{
	int nid = page_to_nid(page);
1071
	list_move(&page->lru, &h->hugepage_freelists[nid]);
1072 1073
	h->free_huge_pages++;
	h->free_huge_pages_node[nid]++;
1074
	SetPageHugeFreed(page);
L
Linus Torvalds 已提交
1075 1076
}

1077
static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
1078 1079
{
	struct page *page;
1080 1081 1082 1083 1084
	bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);

	list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
		if (nocma && is_migrate_cma_page(page))
			continue;
1085

1086 1087 1088 1089 1090
		if (PageHWPoison(page))
			continue;

		list_move(&page->lru, &h->hugepage_activelist);
		set_page_refcounted(page);
1091
		ClearPageHugeFreed(page);
1092 1093 1094
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
		return page;
1095 1096
	}

1097
	return NULL;
1098 1099
}

1100 1101
static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
		nodemask_t *nmask)
1102
{
1103 1104 1105 1106
	unsigned int cpuset_mems_cookie;
	struct zonelist *zonelist;
	struct zone *zone;
	struct zoneref *z;
1107
	int node = NUMA_NO_NODE;
1108

1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124
	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);
1125 1126 1127 1128 1129

		page = dequeue_huge_page_node_exact(h, node);
		if (page)
			return page;
	}
1130 1131 1132
	if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
		goto retry_cpuset;

1133 1134 1135
	return NULL;
}

1136 1137
static struct page *dequeue_huge_page_vma(struct hstate *h,
				struct vm_area_struct *vma,
1138 1139
				unsigned long address, int avoid_reserve,
				long chg)
L
Linus Torvalds 已提交
1140
{
1141
	struct page *page;
1142
	struct mempolicy *mpol;
1143
	gfp_t gfp_mask;
1144
	nodemask_t *nodemask;
1145
	int nid;
L
Linus Torvalds 已提交
1146

1147 1148 1149 1150 1151
	/*
	 * 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
	 */
1152
	if (!vma_has_reserves(vma, chg) &&
1153
			h->free_huge_pages - h->resv_huge_pages == 0)
1154
		goto err;
1155

1156
	/* If reserves cannot be used, ensure enough pages are in the pool */
1157
	if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
1158
		goto err;
1159

1160 1161
	gfp_mask = htlb_alloc_mask(h);
	nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1162 1163 1164 1165
	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
1166
	}
1167

1168
	mpol_cond_put(mpol);
L
Linus Torvalds 已提交
1169
	return page;
1170 1171 1172

err:
	return NULL;
L
Linus Torvalds 已提交
1173 1174
}

1175 1176 1177 1178 1179 1180 1181 1182 1183
/*
 * 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)
{
1184
	nid = next_node_in(nid, *nodes_allowed);
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 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245
	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--)

1246
#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
1247
static void destroy_compound_gigantic_page(struct page *page,
1248
					unsigned int order)
1249 1250 1251 1252 1253
{
	int i;
	int nr_pages = 1 << order;
	struct page *p = page + 1;

1254
	atomic_set(compound_mapcount_ptr(page), 0);
1255 1256 1257
	if (hpage_pincount_available(page))
		atomic_set(compound_pincount_ptr(page), 0);

1258
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1259
		clear_compound_head(p);
1260 1261 1262 1263
		set_page_refcounted(p);
	}

	set_compound_order(page, 0);
1264
	page[1].compound_nr = 0;
1265 1266 1267
	__ClearPageHead(page);
}

1268
static void free_gigantic_page(struct page *page, unsigned int order)
1269
{
1270 1271 1272 1273
	/*
	 * If the page isn't allocated using the cma allocator,
	 * cma_release() returns false.
	 */
1274 1275
#ifdef CONFIG_CMA
	if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1276
		return;
1277
#endif
1278

1279 1280 1281
	free_contig_range(page_to_pfn(page), 1 << order);
}

1282
#ifdef CONFIG_CONTIG_ALLOC
1283 1284
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
		int nid, nodemask_t *nodemask)
1285
{
1286
	unsigned long nr_pages = 1UL << huge_page_order(h);
1287 1288
	if (nid == NUMA_NO_NODE)
		nid = numa_mem_id();
1289

1290 1291
#ifdef CONFIG_CMA
	{
1292 1293 1294
		struct page *page;
		int node;

1295 1296 1297
		if (hugetlb_cma[nid]) {
			page = cma_alloc(hugetlb_cma[nid], nr_pages,
					huge_page_order(h), true);
1298 1299 1300
			if (page)
				return page;
		}
1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312

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

				page = cma_alloc(hugetlb_cma[node], nr_pages,
						huge_page_order(h), true);
				if (page)
					return page;
			}
		}
1313
	}
1314
#endif
1315

1316
	return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1317 1318 1319
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1320
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1321 1322 1323 1324 1325 1326 1327
#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 */
1328

1329
#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1330
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1331 1332 1333 1334
					int nid, nodemask_t *nodemask)
{
	return NULL;
}
1335
static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1336
static inline void destroy_compound_gigantic_page(struct page *page,
1337
						unsigned int order) { }
1338 1339
#endif

1340
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1341 1342
{
	int i;
1343
	struct page *subpage = page;
1344

1345
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1346
		return;
1347

1348 1349
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
1350 1351 1352
	for (i = 0; i < pages_per_huge_page(h);
	     i++, subpage = mem_map_next(subpage, page, i)) {
		subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
1353
				1 << PG_referenced | 1 << PG_dirty |
1354 1355
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1356
	}
1357
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1358
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1359
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1360
	set_page_refcounted(page);
1361
	if (hstate_is_gigantic(h)) {
1362 1363 1364 1365 1366
		/*
		 * Temporarily drop the hugetlb_lock, because
		 * we might block in free_gigantic_page().
		 */
		spin_unlock(&hugetlb_lock);
1367 1368
		destroy_compound_gigantic_page(page, huge_page_order(h));
		free_gigantic_page(page, huge_page_order(h));
1369
		spin_lock(&hugetlb_lock);
1370 1371 1372
	} else {
		__free_pages(page, huge_page_order(h));
	}
A
Adam Litke 已提交
1373 1374
}

1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385
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;
}

1386 1387 1388 1389 1390 1391 1392 1393
/*
 * 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)
{
1394
	return PageHeadHuge(page) && PagePrivate(&page[1]);
1395 1396 1397
}

/* never called for tail page */
1398
void set_page_huge_active(struct page *page)
1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409
{
	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]);
}

1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431
/*
 * 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;
}

1432
static void __free_huge_page(struct page *page)
1433
{
1434 1435 1436 1437
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1438
	struct hstate *h = page_hstate(page);
1439
	int nid = page_to_nid(page);
1440 1441
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1442
	bool restore_reserve;
1443

1444 1445
	VM_BUG_ON_PAGE(page_count(page), page);
	VM_BUG_ON_PAGE(page_mapcount(page), page);
1446 1447 1448

	set_page_private(page, 0);
	page->mapping = NULL;
1449
	restore_reserve = PagePrivate(page);
1450
	ClearPagePrivate(page);
1451

1452
	/*
1453 1454 1455 1456 1457 1458
	 * 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.
1459
	 */
1460 1461 1462 1463 1464 1465 1466 1467 1468 1469
	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;
	}
1470

1471
	spin_lock(&hugetlb_lock);
1472
	clear_page_huge_active(page);
1473 1474
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1475 1476
	hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
					  pages_per_huge_page(h), page);
1477 1478 1479
	if (restore_reserve)
		h->resv_huge_pages++;

1480 1481 1482 1483 1484
	if (PageHugeTemporary(page)) {
		list_del(&page->lru);
		ClearPageHugeTemporary(page);
		update_and_free_page(h, page);
	} else if (h->surplus_huge_pages_node[nid]) {
1485 1486
		/* remove the page from active list */
		list_del(&page->lru);
1487 1488 1489
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1490
	} else {
1491
		arch_clear_hugepage_flags(page);
1492
		enqueue_huge_page(h, page);
1493
	}
1494 1495 1496
	spin_unlock(&hugetlb_lock);
}

1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544
/*
 * 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);
}

1545
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1546
{
1547
	INIT_LIST_HEAD(&page->lru);
1548
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1549
	set_hugetlb_cgroup(page, NULL);
1550
	set_hugetlb_cgroup_rsvd(page, NULL);
1551
	spin_lock(&hugetlb_lock);
1552 1553
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1554
	ClearPageHugeFreed(page);
1555 1556 1557
	spin_unlock(&hugetlb_lock);
}

1558
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1559 1560 1561 1562 1563 1564 1565
{
	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);
1566
	__ClearPageReserved(page);
1567
	__SetPageHead(page);
1568
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1569 1570 1571 1572
		/*
		 * 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
1573
		 * too.  Otherwise drivers using get_user_pages() to access tail
1574 1575 1576 1577 1578 1579 1580 1581
		 * 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);
1582
		set_page_count(p, 0);
1583
		set_compound_head(p, page);
1584
	}
1585
	atomic_set(compound_mapcount_ptr(page), -1);
1586 1587 1588

	if (hpage_pincount_available(page))
		atomic_set(compound_pincount_ptr(page), 0);
1589 1590
}

A
Andrew Morton 已提交
1591 1592 1593 1594 1595
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1596 1597 1598 1599 1600 1601
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1602
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1603
}
1604 1605
EXPORT_SYMBOL_GPL(PageHuge);

1606 1607 1608 1609 1610 1611 1612 1613 1614
/*
 * 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;

1615
	return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1616 1617
}

1618 1619 1620
/*
 * Find and lock address space (mapping) in write mode.
 *
1621 1622 1623
 * Upon entry, the page is locked which means that page_mapping() is
 * stable.  Due to locking order, we can only trylock_write.  If we can
 * not get the lock, simply return NULL to caller.
1624 1625 1626
 */
struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
{
1627
	struct address_space *mapping = page_mapping(hpage);
1628 1629 1630 1631 1632 1633 1634

	if (!mapping)
		return mapping;

	if (i_mmap_trylock_write(mapping))
		return mapping;

1635
	return NULL;
1636 1637
}

1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654
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;
}

1655
static struct page *alloc_buddy_huge_page(struct hstate *h,
1656 1657
		gfp_t gfp_mask, int nid, nodemask_t *nmask,
		nodemask_t *node_alloc_noretry)
L
Linus Torvalds 已提交
1658
{
1659
	int order = huge_page_order(h);
L
Linus Torvalds 已提交
1660
	struct page *page;
1661
	bool alloc_try_hard = true;
1662

1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674
	/*
	 * 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;
1675 1676 1677 1678 1679 1680 1681
	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);
1682

1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698
	/*
	 * 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);

1699 1700 1701
	return page;
}

1702 1703 1704 1705 1706
/*
 * 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,
1707 1708
		gfp_t gfp_mask, int nid, nodemask_t *nmask,
		nodemask_t *node_alloc_noretry)
1709 1710 1711 1712 1713 1714 1715
{
	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,
1716
				nid, nmask, node_alloc_noretry);
1717 1718 1719 1720 1721 1722 1723 1724 1725 1726
	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;
}

1727 1728 1729 1730
/*
 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
 * manner.
 */
1731 1732
static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
				nodemask_t *node_alloc_noretry)
1733 1734 1735
{
	struct page *page;
	int nr_nodes, node;
1736
	gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1737 1738

	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1739 1740
		page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
						node_alloc_noretry);
1741
		if (page)
1742 1743 1744
			break;
	}

1745 1746
	if (!page)
		return 0;
1747

1748 1749 1750
	put_page(page); /* free it into the hugepage allocator */

	return 1;
1751 1752
}

1753 1754 1755 1756 1757 1758
/*
 * 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.
 */
1759 1760
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1761
{
1762
	int nr_nodes, node;
1763 1764
	int ret = 0;

1765
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1766 1767 1768 1769
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1770 1771
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1772
			struct page *page =
1773
				list_entry(h->hugepage_freelists[node].next,
1774 1775 1776
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1777
			h->free_huge_pages_node[node]--;
1778 1779
			if (acct_surplus) {
				h->surplus_huge_pages--;
1780
				h->surplus_huge_pages_node[node]--;
1781
			}
1782 1783
			update_and_free_page(h, page);
			ret = 1;
1784
			break;
1785
		}
1786
	}
1787 1788 1789 1790

	return ret;
}

1791 1792
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
1793 1794 1795 1796 1797 1798 1799
 * 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)
1800
 */
1801
int dissolve_free_huge_page(struct page *page)
1802
{
1803
	int rc = -EBUSY;
1804

1805
retry:
1806 1807 1808 1809
	/* Not to disrupt normal path by vainly holding hugetlb_lock */
	if (!PageHuge(page))
		return 0;

1810
	spin_lock(&hugetlb_lock);
1811 1812 1813 1814 1815 1816
	if (!PageHuge(page)) {
		rc = 0;
		goto out;
	}

	if (!page_count(page)) {
1817 1818 1819
		struct page *head = compound_head(page);
		struct hstate *h = page_hstate(head);
		int nid = page_to_nid(head);
1820
		if (h->free_huge_pages - h->resv_huge_pages == 0)
1821
			goto out;
1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841

		/*
		 * We should make sure that the page is already on the free list
		 * when it is dissolved.
		 */
		if (unlikely(!PageHugeFreed(head))) {
			spin_unlock(&hugetlb_lock);
			cond_resched();

			/*
			 * Theoretically, we should return -EBUSY when we
			 * encounter this race. In fact, we have a chance
			 * to successfully dissolve the page if we do a
			 * retry. Because the race window is quite small.
			 * If we seize this opportunity, it is an optimization
			 * for increasing the success rate of dissolving page.
			 */
			goto retry;
		}

1842 1843 1844 1845 1846 1847 1848 1849
		/*
		 * 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);
		}
1850
		list_del(&head->lru);
1851 1852
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
1853
		h->max_huge_pages--;
1854
		update_and_free_page(h, head);
1855
		rc = 0;
1856
	}
1857
out:
1858
	spin_unlock(&hugetlb_lock);
1859
	return rc;
1860 1861 1862 1863 1864
}

/*
 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 * make specified memory blocks removable from the system.
1865 1866
 * Note that this will dissolve a free gigantic hugepage completely, if any
 * part of it lies within the given range.
1867 1868
 * Also note that if dissolve_free_huge_page() returns with an error, all
 * free hugepages that were dissolved before that error are lost.
1869
 */
1870
int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1871 1872
{
	unsigned long pfn;
1873
	struct page *page;
1874
	int rc = 0;
1875

1876
	if (!hugepages_supported())
1877
		return rc;
1878

1879 1880
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
		page = pfn_to_page(pfn);
1881 1882 1883
		rc = dissolve_free_huge_page(page);
		if (rc)
			break;
1884
	}
1885 1886

	return rc;
1887 1888
}

1889 1890 1891
/*
 * Allocates a fresh surplus page from the page allocator.
 */
1892
static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1893
		int nid, nodemask_t *nmask)
1894
{
1895
	struct page *page = NULL;
1896

1897
	if (hstate_is_gigantic(h))
1898 1899
		return NULL;

1900
	spin_lock(&hugetlb_lock);
1901 1902
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
		goto out_unlock;
1903 1904
	spin_unlock(&hugetlb_lock);

1905
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1906
	if (!page)
1907
		return NULL;
1908 1909

	spin_lock(&hugetlb_lock);
1910 1911 1912 1913 1914 1915 1916 1917 1918
	/*
	 * 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);
1919
		spin_unlock(&hugetlb_lock);
1920
		put_page(page);
1921
		return NULL;
1922 1923
	} else {
		h->surplus_huge_pages++;
1924
		h->surplus_huge_pages_node[page_to_nid(page)]++;
1925
	}
1926 1927

out_unlock:
1928
	spin_unlock(&hugetlb_lock);
1929 1930 1931 1932

	return page;
}

1933
static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1934
				     int nid, nodemask_t *nmask)
1935 1936 1937 1938 1939 1940
{
	struct page *page;

	if (hstate_is_gigantic(h))
		return NULL;

1941
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953
	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;
}

1954 1955 1956
/*
 * Use the VMA's mpolicy to allocate a huge page from the buddy.
 */
D
Dave Hansen 已提交
1957
static
1958
struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1959 1960
		struct vm_area_struct *vma, unsigned long addr)
{
1961 1962 1963 1964 1965 1966 1967
	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);
1968
	page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1969 1970 1971
	mpol_cond_put(mpol);

	return page;
1972 1973
}

1974
/* page migration callback function */
1975
struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1976
		nodemask_t *nmask, gfp_t gfp_mask)
1977 1978 1979
{
	spin_lock(&hugetlb_lock);
	if (h->free_huge_pages - h->resv_huge_pages > 0) {
1980 1981 1982 1983 1984 1985
		struct page *page;

		page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
		if (page) {
			spin_unlock(&hugetlb_lock);
			return page;
1986 1987 1988 1989
		}
	}
	spin_unlock(&hugetlb_lock);

1990
	return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1991 1992
}

1993
/* mempolicy aware migration callback */
1994 1995
struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
		unsigned long address)
1996 1997 1998 1999 2000 2001 2002 2003 2004
{
	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);
2005
	page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
2006 2007 2008 2009 2010
	mpol_cond_put(mpol);

	return page;
}

2011
/*
L
Lucas De Marchi 已提交
2012
 * Increase the hugetlb pool such that it can accommodate a reservation
2013 2014
 * of size 'delta'.
 */
2015
static int gather_surplus_pages(struct hstate *h, int delta)
2016
	__must_hold(&hugetlb_lock)
2017 2018 2019 2020 2021
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
2022
	bool alloc_ok = true;
2023

2024
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
2025
	if (needed <= 0) {
2026
		h->resv_huge_pages += delta;
2027
		return 0;
2028
	}
2029 2030 2031 2032 2033 2034 2035 2036

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
2037
		page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
2038
				NUMA_NO_NODE, NULL);
2039 2040 2041 2042
		if (!page) {
			alloc_ok = false;
			break;
		}
2043
		list_add(&page->lru, &surplus_list);
2044
		cond_resched();
2045
	}
2046
	allocated += i;
2047 2048 2049 2050 2051 2052

	/*
	 * 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);
2053 2054
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
2055 2056 2057 2058 2059 2060 2061 2062 2063 2064
	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;
	}
2065 2066
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
2067
	 * needed to accommodate the reservation.  Add the appropriate number
2068
	 * of pages to the hugetlb pool and free the extras back to the buddy
2069 2070 2071
	 * 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.
2072 2073
	 */
	needed += allocated;
2074
	h->resv_huge_pages += delta;
2075
	ret = 0;
2076

2077
	/* Free the needed pages to the hugetlb pool */
2078
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2079 2080
		if ((--needed) < 0)
			break;
2081 2082 2083 2084 2085
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
2086
		VM_BUG_ON_PAGE(page_count(page), page);
2087
		enqueue_huge_page(h, page);
2088
	}
2089
free:
2090
	spin_unlock(&hugetlb_lock);
2091 2092

	/* Free unnecessary surplus pages to the buddy allocator */
2093 2094
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
2095
	spin_lock(&hugetlb_lock);
2096 2097 2098 2099 2100

	return ret;
}

/*
2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112
 * 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.
2113
 */
2114 2115
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
2116 2117 2118
{
	unsigned long nr_pages;

2119
	/* Cannot return gigantic pages currently */
2120
	if (hstate_is_gigantic(h))
2121
		goto out;
2122

2123 2124 2125 2126
	/*
	 * Part (or even all) of the reservation could have been backed
	 * by pre-allocated pages. Only free surplus pages.
	 */
2127
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2128

2129 2130
	/*
	 * We want to release as many surplus pages as possible, spread
2131 2132 2133
	 * 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.
2134
	 * free_pool_huge_page() will balance the freed pages across the
2135
	 * on-line nodes with memory and will handle the hstate accounting.
2136 2137 2138 2139
	 *
	 * 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.
2140 2141
	 */
	while (nr_pages--) {
2142 2143
		h->resv_huge_pages--;
		unused_resv_pages--;
2144
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
2145
			goto out;
2146
		cond_resched_lock(&hugetlb_lock);
2147
	}
2148 2149 2150 2151

out:
	/* Fully uncommit the reservation */
	h->resv_huge_pages -= unused_resv_pages;
2152 2153
}

2154

2155
/*
2156
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2157
 * are used by the huge page allocation routines to manage reservations.
2158 2159 2160 2161 2162 2163
 *
 * 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
2164 2165 2166
 * 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.
2167 2168 2169 2170 2171 2172
 *
 * 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.
2173 2174 2175 2176 2177
 *
 * 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.
2178
 */
2179 2180 2181
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
2182
	VMA_END_RESV,
2183
	VMA_ADD_RESV,
2184
};
2185 2186
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
2187
				enum vma_resv_mode mode)
2188
{
2189 2190
	struct resv_map *resv;
	pgoff_t idx;
2191
	long ret;
2192
	long dummy_out_regions_needed;
2193

2194 2195
	resv = vma_resv_map(vma);
	if (!resv)
2196
		return 1;
2197

2198
	idx = vma_hugecache_offset(h, vma, addr);
2199 2200
	switch (mode) {
	case VMA_NEEDS_RESV:
2201 2202 2203 2204 2205 2206
		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);
2207 2208
		break;
	case VMA_COMMIT_RESV:
2209
		ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2210 2211
		/* region_add calls of range 1 should never fail. */
		VM_BUG_ON(ret < 0);
2212
		break;
2213
	case VMA_END_RESV:
2214
		region_abort(resv, idx, idx + 1, 1);
2215 2216
		ret = 0;
		break;
2217
	case VMA_ADD_RESV:
2218
		if (vma->vm_flags & VM_MAYSHARE) {
2219
			ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2220 2221 2222 2223
			/* region_add calls of range 1 should never fail. */
			VM_BUG_ON(ret < 0);
		} else {
			region_abort(resv, idx, idx + 1, 1);
2224 2225 2226
			ret = region_del(resv, idx, idx + 1);
		}
		break;
2227 2228 2229
	default:
		BUG();
	}
2230

2231
	if (vma->vm_flags & VM_MAYSHARE)
2232
		return ret;
2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251
	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;
	}
2252
	else
2253
		return ret < 0 ? ret : 0;
2254
}
2255 2256

static long vma_needs_reservation(struct hstate *h,
2257
			struct vm_area_struct *vma, unsigned long addr)
2258
{
2259
	return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2260
}
2261

2262 2263 2264
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
2265 2266 2267
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

2268
static void vma_end_reservation(struct hstate *h,
2269 2270
			struct vm_area_struct *vma, unsigned long addr)
{
2271
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2272 2273
}

2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323
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);
	}
}

2324
struct page *alloc_huge_page(struct vm_area_struct *vma,
2325
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
2326
{
2327
	struct hugepage_subpool *spool = subpool_vma(vma);
2328
	struct hstate *h = hstate_vma(vma);
2329
	struct page *page;
2330 2331
	long map_chg, map_commit;
	long gbl_chg;
2332 2333
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
2334
	bool deferred_reserve;
2335

2336
	idx = hstate_index(h);
2337
	/*
2338 2339 2340
	 * 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).
2341
	 */
2342 2343
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
2344
		return ERR_PTR(-ENOMEM);
2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355

	/*
	 * 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) {
2356
			vma_end_reservation(h, vma, addr);
2357
			return ERR_PTR(-ENOSPC);
2358
		}
L
Linus Torvalds 已提交
2359

2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371
		/*
		 * 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;
	}

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

2382
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2383
	if (ret)
2384
		goto out_uncharge_cgroup_reservation;
2385

L
Linus Torvalds 已提交
2386
	spin_lock(&hugetlb_lock);
2387 2388 2389 2390 2391 2392
	/*
	 * 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);
2393
	if (!page) {
2394
		spin_unlock(&hugetlb_lock);
2395
		page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2396 2397
		if (!page)
			goto out_uncharge_cgroup;
2398 2399 2400 2401
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
2402
		spin_lock(&hugetlb_lock);
2403
		list_add(&page->lru, &h->hugepage_activelist);
2404
		/* Fall through */
K
Ken Chen 已提交
2405
	}
2406
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2407 2408 2409 2410 2411 2412 2413 2414
	/* 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);
	}

2415
	spin_unlock(&hugetlb_lock);
2416

2417
	set_page_private(page, (unsigned long)spool);
2418

2419 2420
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433
		/*
		 * 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);
2434 2435 2436
		if (deferred_reserve)
			hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
					pages_per_huge_page(h), page);
2437
	}
2438
	return page;
2439 2440 2441

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2442 2443 2444 2445
out_uncharge_cgroup_reservation:
	if (deferred_reserve)
		hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
						    h_cg);
2446
out_subpool_put:
2447
	if (map_chg || avoid_reserve)
2448
		hugepage_subpool_put_pages(spool, 1);
2449
	vma_end_reservation(h, vma, addr);
2450
	return ERR_PTR(-ENOSPC);
2451 2452
}

2453 2454 2455
int alloc_bootmem_huge_page(struct hstate *h)
	__attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
int __alloc_bootmem_huge_page(struct hstate *h)
2456 2457
{
	struct huge_bootmem_page *m;
2458
	int nr_nodes, node;
2459

2460
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2461 2462
		void *addr;

2463
		addr = memblock_alloc_try_nid_raw(
2464
				huge_page_size(h), huge_page_size(h),
2465
				0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2466 2467 2468 2469 2470 2471 2472
		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;
2473
			goto found;
2474 2475 2476 2477 2478
		}
	}
	return 0;

found:
2479
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2480
	/* Put them into a private list first because mem_map is not up yet */
2481
	INIT_LIST_HEAD(&m->list);
2482 2483 2484 2485 2486
	list_add(&m->list, &huge_boot_pages);
	m->hstate = h;
	return 1;
}

2487 2488
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
2489 2490 2491 2492 2493 2494 2495
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

2496 2497 2498 2499 2500 2501
/* 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) {
2502
		struct page *page = virt_to_page(m);
2503
		struct hstate *h = m->hstate;
2504

2505
		WARN_ON(page_count(page) != 1);
2506
		prep_compound_huge_page(page, h->order);
2507
		WARN_ON(PageReserved(page));
2508
		prep_new_huge_page(h, page, page_to_nid(page));
2509 2510
		put_page(page); /* free it into the hugepage allocator */

2511 2512 2513 2514 2515 2516
		/*
		 * 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.
		 */
2517
		if (hstate_is_gigantic(h))
2518
			adjust_managed_page_count(page, 1 << h->order);
2519
		cond_resched();
2520 2521 2522
	}
}

2523
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2524 2525
{
	unsigned long i;
2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544
	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);
2545

2546
	for (i = 0; i < h->max_huge_pages; ++i) {
2547
		if (hstate_is_gigantic(h)) {
2548
			if (hugetlb_cma_size) {
2549
				pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
2550
				goto free;
2551
			}
2552 2553
			if (!alloc_bootmem_huge_page(h))
				break;
2554
		} else if (!alloc_pool_huge_page(h,
2555 2556
					 &node_states[N_MEMORY],
					 node_alloc_noretry))
L
Linus Torvalds 已提交
2557
			break;
2558
		cond_resched();
L
Linus Torvalds 已提交
2559
	}
2560 2561 2562
	if (i < h->max_huge_pages) {
		char buf[32];

2563
		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2564 2565 2566 2567
		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;
	}
2568
free:
2569
	kfree(node_alloc_noretry);
2570 2571 2572 2573 2574 2575 2576
}

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

	for_each_hstate(h) {
2577 2578 2579
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2580
		/* oversize hugepages were init'ed in early boot */
2581
		if (!hstate_is_gigantic(h))
2582
			hugetlb_hstate_alloc_pages(h);
2583
	}
2584
	VM_BUG_ON(minimum_order == UINT_MAX);
2585 2586 2587 2588 2589 2590 2591
}

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

	for_each_hstate(h) {
A
Andi Kleen 已提交
2592
		char buf[32];
2593 2594

		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2595
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2596
			buf, h->free_huge_pages);
2597 2598 2599
	}
}

L
Linus Torvalds 已提交
2600
#ifdef CONFIG_HIGHMEM
2601 2602
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2603
{
2604 2605
	int i;

2606
	if (hstate_is_gigantic(h))
2607 2608
		return;

2609
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2610
		struct page *page, *next;
2611 2612 2613
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2614
				return;
L
Linus Torvalds 已提交
2615 2616 2617
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2618
			update_and_free_page(h, page);
2619 2620
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2621 2622 2623 2624
		}
	}
}
#else
2625 2626
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2627 2628 2629 2630
{
}
#endif

2631 2632 2633 2634 2635
/*
 * 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.
 */
2636 2637
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2638
{
2639
	int nr_nodes, node;
2640 2641 2642

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

2643 2644 2645 2646
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2647
		}
2648 2649 2650 2651 2652
	} 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;
2653
		}
2654 2655
	}
	return 0;
2656

2657 2658 2659 2660
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2661 2662
}

2663
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2664
static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2665
			      nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2666
{
2667
	unsigned long min_count, ret;
2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678
	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
2679

2680 2681
	spin_lock(&hugetlb_lock);

2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701
	/*
	 * 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;
	}

2702 2703 2704 2705 2706 2707 2708 2709 2710 2711
	/*
	 * 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);
2712
			NODEMASK_FREE(node_alloc_noretry);
2713 2714 2715 2716
			return -EINVAL;
		}
		/* Fall through to decrease pool */
	}
2717

2718 2719 2720 2721
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2722
	 *
2723
	 * We might race with alloc_surplus_huge_page() here and be unable
2724 2725 2726 2727
	 * 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.
2728
	 */
2729
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2730
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2731 2732 2733
			break;
	}

2734
	while (count > persistent_huge_pages(h)) {
2735 2736 2737 2738 2739 2740
		/*
		 * 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);
2741 2742 2743 2744

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

2745 2746
		ret = alloc_pool_huge_page(h, nodes_allowed,
						node_alloc_noretry);
2747 2748 2749 2750
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2751 2752 2753
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2754 2755 2756 2757 2758 2759 2760 2761
	}

	/*
	 * 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.
2762 2763 2764 2765
	 *
	 * 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
2766
	 * alloc_surplus_huge_page() is checking the global counter,
2767 2768 2769
	 * 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.
2770
	 */
2771
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2772
	min_count = max(count, min_count);
2773
	try_to_free_low(h, min_count, nodes_allowed);
2774
	while (min_count < persistent_huge_pages(h)) {
2775
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2776
			break;
2777
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2778
	}
2779
	while (count < persistent_huge_pages(h)) {
2780
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2781 2782 2783
			break;
	}
out:
2784
	h->max_huge_pages = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2785
	spin_unlock(&hugetlb_lock);
2786

2787 2788
	NODEMASK_FREE(node_alloc_noretry);

2789
	return 0;
L
Linus Torvalds 已提交
2790 2791
}

2792 2793 2794 2795 2796 2797 2798 2799 2800 2801
#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];

2802 2803 2804
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2805 2806
{
	int i;
2807

2808
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2809 2810 2811
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2812
			return &hstates[i];
2813 2814 2815
		}

	return kobj_to_node_hstate(kobj, nidp);
2816 2817
}

2818
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2819 2820
					struct kobj_attribute *attr, char *buf)
{
2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831
	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);
2832
}
2833

2834 2835 2836
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2837 2838
{
	int err;
2839
	nodemask_t nodes_allowed, *n_mask;
2840

2841 2842
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
		return -EINVAL;
2843

2844 2845 2846 2847 2848
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
2849 2850 2851 2852 2853
				init_nodemask_of_mempolicy(&nodes_allowed)))
			n_mask = &node_states[N_MEMORY];
		else
			n_mask = &nodes_allowed;
	} else {
2854
		/*
2855 2856
		 * Node specific request.  count adjustment happens in
		 * set_max_huge_pages() after acquiring hugetlb_lock.
2857
		 */
2858 2859
		init_nodemask_of_node(&nodes_allowed, nid);
		n_mask = &nodes_allowed;
2860
	}
2861

2862
	err = set_max_huge_pages(h, count, nid, n_mask);
2863

2864
	return err ? err : len;
2865 2866
}

2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883
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);
}

2884 2885 2886 2887 2888 2889 2890 2891 2892
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)
{
2893
	return nr_hugepages_store_common(false, kobj, buf, len);
2894 2895 2896
}
HSTATE_ATTR(nr_hugepages);

2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911
#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)
{
2912
	return nr_hugepages_store_common(true, kobj, buf, len);
2913 2914 2915 2916 2917
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2918 2919 2920
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2921
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2922 2923
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2924

2925 2926 2927 2928 2929
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;
2930
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2931

2932
	if (hstate_is_gigantic(h))
2933 2934
		return -EINVAL;

2935
	err = kstrtoul(buf, 10, &input);
2936
	if (err)
2937
		return err;
2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949

	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)
{
2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960
	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);
2961 2962 2963 2964 2965 2966
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2967
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2968 2969 2970 2971 2972 2973 2974
	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)
{
2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985
	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);
2986 2987 2988 2989 2990 2991 2992 2993 2994
}
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,
2995 2996 2997
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
2998 2999 3000
	NULL,
};

3001
static const struct attribute_group hstate_attr_group = {
3002 3003 3004
	.attrs = hstate_attrs,
};

J
Jeff Mahoney 已提交
3005 3006
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
3007
				    const struct attribute_group *hstate_attr_group)
3008 3009
{
	int retval;
3010
	int hi = hstate_index(h);
3011

3012 3013
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
3014 3015
		return -ENOMEM;

3016
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
3017
	if (retval) {
3018
		kobject_put(hstate_kobjs[hi]);
3019 3020
		hstate_kobjs[hi] = NULL;
	}
3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034

	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) {
3035 3036
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
3037
		if (err)
3038
			pr_err("HugeTLB: Unable to add hstate %s", h->name);
3039 3040 3041
	}
}

3042 3043 3044 3045
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
3046 3047 3048
 * 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
3049 3050 3051 3052 3053 3054
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
3055
static struct node_hstate node_hstates[MAX_NUMNODES];
3056 3057

/*
3058
 * A subset of global hstate attributes for node devices
3059 3060 3061 3062 3063 3064 3065 3066
 */
static struct attribute *per_node_hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
	NULL,
};

3067
static const struct attribute_group per_node_hstate_attr_group = {
3068 3069 3070 3071
	.attrs = per_node_hstate_attrs,
};

/*
3072
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094
 * 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;
}

/*
3095
 * Unregister hstate attributes from a single node device.
3096 3097
 * No-op if no hstate attributes attached.
 */
3098
static void hugetlb_unregister_node(struct node *node)
3099 3100
{
	struct hstate *h;
3101
	struct node_hstate *nhs = &node_hstates[node->dev.id];
3102 3103

	if (!nhs->hugepages_kobj)
3104
		return;		/* no hstate attributes */
3105

3106 3107 3108 3109 3110
	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;
3111
		}
3112
	}
3113 3114 3115 3116 3117 3118 3119

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


/*
3120
 * Register hstate attributes for a single node device.
3121 3122
 * No-op if attributes already registered.
 */
3123
static void hugetlb_register_node(struct node *node)
3124 3125
{
	struct hstate *h;
3126
	struct node_hstate *nhs = &node_hstates[node->dev.id];
3127 3128 3129 3130 3131 3132
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3133
							&node->dev.kobj);
3134 3135 3136 3137 3138 3139 3140 3141
	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) {
3142
			pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3143
				h->name, node->dev.id);
3144 3145 3146 3147 3148 3149 3150
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
3151
 * hugetlb init time:  register hstate attributes for all registered node
3152 3153
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
3154
 */
3155
static void __init hugetlb_register_all_nodes(void)
3156 3157 3158
{
	int nid;

3159
	for_each_node_state(nid, N_MEMORY) {
3160
		struct node *node = node_devices[nid];
3161
		if (node->dev.id == nid)
3162 3163 3164 3165
			hugetlb_register_node(node);
	}

	/*
3166
	 * Let the node device driver know we're here so it can
3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185
	 * [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

3186 3187
static int __init hugetlb_init(void)
{
3188 3189
	int i;

3190 3191 3192
	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");
3193
		return 0;
3194
	}
3195

3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223
	/*
	 * 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;
3224
		}
3225
	}
3226

3227
	hugetlb_cma_check();
3228
	hugetlb_init_hstates();
3229
	gather_bootmem_prealloc();
3230 3231 3232
	report_hugepages();

	hugetlb_sysfs_init();
3233
	hugetlb_register_all_nodes();
3234
	hugetlb_cgroup_file_init();
3235

3236 3237 3238 3239 3240
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
3241
	hugetlb_fault_mutex_table =
3242 3243
		kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
			      GFP_KERNEL);
3244
	BUG_ON(!hugetlb_fault_mutex_table);
3245 3246

	for (i = 0; i < num_fault_mutexes; i++)
3247
		mutex_init(&hugetlb_fault_mutex_table[i]);
3248 3249
	return 0;
}
3250
subsys_initcall(hugetlb_init);
3251

3252 3253
/* Overwritten by architectures with more huge page sizes */
bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3254
{
3255
	return size == HPAGE_SIZE;
3256 3257
}

3258
void __init hugetlb_add_hstate(unsigned int order)
3259 3260
{
	struct hstate *h;
3261 3262
	unsigned long i;

3263 3264 3265
	if (size_to_hstate(PAGE_SIZE << order)) {
		return;
	}
3266
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3267
	BUG_ON(order == 0);
3268
	h = &hstates[hugetlb_max_hstate++];
3269 3270
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
3271 3272 3273 3274
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3275
	INIT_LIST_HEAD(&h->hugepage_activelist);
3276 3277
	h->next_nid_to_alloc = first_memory_node;
	h->next_nid_to_free = first_memory_node;
3278 3279
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
3280

3281 3282 3283
	parsed_hstate = h;
}

3284 3285 3286 3287 3288 3289 3290 3291
/*
 * 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)
3292 3293
{
	unsigned long *mhp;
3294
	static unsigned long *last_mhp;
3295

3296
	if (!parsed_valid_hugepagesz) {
3297
		pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3298
		parsed_valid_hugepagesz = true;
3299
		return 0;
3300
	}
3301

3302
	/*
3303 3304 3305 3306
	 * !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.
3307
	 */
3308
	else if (!hugetlb_max_hstate)
3309 3310 3311 3312
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

3313
	if (mhp == last_mhp) {
3314 3315
		pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
		return 0;
3316 3317
	}

3318 3319 3320
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

3321 3322 3323 3324 3325
	/*
	 * 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.
	 */
3326
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
3327 3328 3329 3330
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

3331 3332
	return 1;
}
3333
__setup("hugepages=", hugepages_setup);
3334

3335 3336 3337 3338 3339 3340 3341
/*
 * 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.
 */
3342
static int __init hugepagesz_setup(char *s)
3343
{
3344
	unsigned long size;
3345 3346 3347
	struct hstate *h;

	parsed_valid_hugepagesz = false;
3348 3349 3350
	size = (unsigned long)memparse(s, NULL);

	if (!arch_hugetlb_valid_size(size)) {
3351
		pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3352 3353 3354
		return 0;
	}

3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377
	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;
3378 3379
	}

3380
	hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3381
	parsed_valid_hugepagesz = true;
3382 3383
	return 1;
}
3384 3385
__setup("hugepagesz=", hugepagesz_setup);

3386 3387 3388 3389
/*
 * default_hugepagesz command line input
 * Only one instance of default_hugepagesz allowed on command line.
 */
3390
static int __init default_hugepagesz_setup(char *s)
3391
{
3392 3393
	unsigned long size;

3394 3395 3396 3397 3398 3399
	parsed_valid_hugepagesz = false;
	if (parsed_default_hugepagesz) {
		pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
		return 0;
	}

3400 3401 3402
	size = (unsigned long)memparse(s, NULL);

	if (!arch_hugetlb_valid_size(size)) {
3403
		pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3404 3405 3406
		return 0;
	}

3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425
	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;
	}

3426 3427
	return 1;
}
3428
__setup("default_hugepagesz=", default_hugepagesz_setup);
3429

3430
static unsigned int allowed_mems_nr(struct hstate *h)
3431 3432 3433
{
	int node;
	unsigned int nr = 0;
3434 3435 3436 3437 3438
	nodemask_t *mpol_allowed;
	unsigned int *array = h->free_huge_pages_node;
	gfp_t gfp_mask = htlb_alloc_mask(h);

	mpol_allowed = policy_nodemask_current(gfp_mask);
3439

3440 3441 3442 3443 3444
	for_each_node_mask(node, cpuset_current_mems_allowed) {
		if (!mpol_allowed ||
		    (mpol_allowed && node_isset(node, *mpol_allowed)))
			nr += array[node];
	}
3445 3446 3447 3448 3449

	return nr;
}

#ifdef CONFIG_SYSCTL
3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465
static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
					  void *buffer, size_t *length,
					  loff_t *ppos, unsigned long *out)
{
	struct ctl_table dup_table;

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

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

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
	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
					     &tmp);
3479 3480
	if (ret)
		goto out;
3481

3482 3483 3484
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
3485 3486
out:
	return ret;
L
Linus Torvalds 已提交
3487
}
3488

3489
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3490
			  void *buffer, size_t *length, loff_t *ppos)
3491 3492 3493 3494 3495 3496 3497 3498
{

	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,
3499
			  void *buffer, size_t *length, loff_t *ppos)
3500 3501 3502 3503 3504 3505
{
	return hugetlb_sysctl_handler_common(true, table, write,
							buffer, length, ppos);
}
#endif /* CONFIG_NUMA */

3506
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3507
		void *buffer, size_t *length, loff_t *ppos)
3508
{
3509
	struct hstate *h = &default_hstate;
3510
	unsigned long tmp;
3511
	int ret;
3512

3513
	if (!hugepages_supported())
3514
		return -EOPNOTSUPP;
3515

3516
	tmp = h->nr_overcommit_huge_pages;
3517

3518
	if (write && hstate_is_gigantic(h))
3519 3520
		return -EINVAL;

3521 3522
	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
					     &tmp);
3523 3524
	if (ret)
		goto out;
3525 3526 3527 3528 3529 3530

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
3531 3532
out:
	return ret;
3533 3534
}

L
Linus Torvalds 已提交
3535 3536
#endif /* CONFIG_SYSCTL */

3537
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
3538
{
3539 3540 3541
	struct hstate *h;
	unsigned long total = 0;

3542 3543
	if (!hugepages_supported())
		return;
3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564

	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
3565 3566
}

3567
int hugetlb_report_node_meminfo(char *buf, int len, int nid)
L
Linus Torvalds 已提交
3568
{
3569
	struct hstate *h = &default_hstate;
3570

3571 3572
	if (!hugepages_supported())
		return 0;
3573 3574 3575 3576 3577 3578 3579 3580

	return sysfs_emit_at(buf, len,
			     "Node %d HugePages_Total: %5u\n"
			     "Node %d HugePages_Free:  %5u\n"
			     "Node %d HugePages_Surp:  %5u\n",
			     nid, h->nr_huge_pages_node[nid],
			     nid, h->free_huge_pages_node[nid],
			     nid, h->surplus_huge_pages_node[nid]);
L
Linus Torvalds 已提交
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
{
	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.
3639 3640 3641 3642 3643 3644
	 *
	 * Apart from cpuset, we also have memory policy mechanism that
	 * also determines from which node the kernel will allocate memory
	 * in a NUMA system. So similar to cpuset, we also should consider
	 * the memory policy of the current task. Similar to the description
	 * above.
M
Mel Gorman 已提交
3645 3646
	 */
	if (delta > 0) {
3647
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
3648 3649
			goto out;

3650
		if (delta > allowed_mems_nr(h)) {
3651
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
3652 3653 3654 3655 3656 3657
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
3658
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
3659 3660 3661 3662 3663 3664

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

3665 3666
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
3667
	struct resv_map *resv = vma_resv_map(vma);
3668 3669 3670 3671 3672

	/*
	 * 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
3673
	 * has a reference to the reservation map it cannot disappear until
3674 3675 3676
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
3677
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3678
		kref_get(&resv->refs);
3679 3680
}

3681 3682
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
3683
	struct hstate *h = hstate_vma(vma);
3684
	struct resv_map *resv = vma_resv_map(vma);
3685
	struct hugepage_subpool *spool = subpool_vma(vma);
3686
	unsigned long reserve, start, end;
3687
	long gbl_reserve;
3688

3689 3690
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
3691

3692 3693
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
3694

3695
	reserve = (end - start) - region_count(resv, start, end);
3696
	hugetlb_cgroup_uncharge_counter(resv, start, end);
3697
	if (reserve) {
3698 3699 3700 3701 3702 3703
		/*
		 * 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);
3704
	}
3705 3706

	kref_put(&resv->refs, resv_map_release);
3707 3708
}

3709 3710 3711 3712 3713 3714 3715
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;
}

3716 3717 3718 3719 3720 3721 3722
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
3723 3724 3725 3726 3727 3728
/*
 * 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.
 */
3729
static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
L
Linus Torvalds 已提交
3730 3731
{
	BUG();
N
Nick Piggin 已提交
3732
	return 0;
L
Linus Torvalds 已提交
3733 3734
}

3735 3736 3737 3738 3739 3740 3741
/*
 * 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.
 */
3742
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
3743
	.fault = hugetlb_vm_op_fault,
3744
	.open = hugetlb_vm_op_open,
3745
	.close = hugetlb_vm_op_close,
3746
	.split = hugetlb_vm_op_split,
3747
	.pagesize = hugetlb_vm_op_pagesize,
L
Linus Torvalds 已提交
3748 3749
};

3750 3751
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
3752 3753 3754
{
	pte_t entry;

3755
	if (writable) {
3756 3757
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
3758
	} else {
3759 3760
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
3761 3762 3763
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3764
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3765 3766 3767 3768

	return entry;
}

3769 3770 3771 3772 3773
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3774
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3775
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3776
		update_mmu_cache(vma, address, ptep);
3777 3778
}

3779
bool is_hugetlb_entry_migration(pte_t pte)
3780 3781 3782 3783
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3784
		return false;
3785
	swp = pte_to_swp_entry(pte);
3786
	if (is_migration_entry(swp))
3787
		return true;
3788
	else
3789
		return false;
3790 3791
}

3792
static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
3793 3794 3795 3796
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3797
		return false;
3798
	swp = pte_to_swp_entry(pte);
3799
	if (is_hwpoison_entry(swp))
3800
		return true;
3801
	else
3802
		return false;
3803
}
3804

D
David Gibson 已提交
3805 3806 3807
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
			    struct vm_area_struct *vma)
{
3808
	pte_t *src_pte, *dst_pte, entry, dst_entry;
D
David Gibson 已提交
3809
	struct page *ptepage;
3810
	unsigned long addr;
3811
	int cow;
3812 3813
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3814
	struct address_space *mapping = vma->vm_file->f_mapping;
3815
	struct mmu_notifier_range range;
3816
	int ret = 0;
3817 3818

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3819

3820
	if (cow) {
3821
		mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3822
					vma->vm_start,
3823 3824
					vma->vm_end);
		mmu_notifier_invalidate_range_start(&range);
3825 3826 3827 3828 3829 3830 3831 3832
	} 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);
3833
	}
3834

3835
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3836
		spinlock_t *src_ptl, *dst_ptl;
3837
		src_pte = huge_pte_offset(src, addr, sz);
H
Hugh Dickins 已提交
3838 3839
		if (!src_pte)
			continue;
3840
		dst_pte = huge_pte_alloc(dst, addr, sz);
3841 3842 3843 3844
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3845

3846 3847 3848 3849 3850 3851 3852 3853 3854 3855 3856
		/*
		 * 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))
3857 3858
			continue;

3859 3860 3861
		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);
3862
		entry = huge_ptep_get(src_pte);
3863 3864 3865 3866 3867 3868 3869
		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.
			 */
3870 3871 3872 3873 3874 3875 3876 3877 3878 3879 3880 3881
			;
		} 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);
3882 3883
				set_huge_swap_pte_at(src, addr, src_pte,
						     entry, sz);
3884
			}
3885
			set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3886
		} else {
3887
			if (cow) {
3888 3889 3890 3891 3892
				/*
				 * No need to notify as we are downgrading page
				 * table protection not changing it to point
				 * to a new page.
				 *
3893
				 * See Documentation/vm/mmu_notifier.rst
3894
				 */
3895
				huge_ptep_set_wrprotect(src, addr, src_pte);
3896
			}
3897
			entry = huge_ptep_get(src_pte);
3898 3899
			ptepage = pte_page(entry);
			get_page(ptepage);
3900
			page_dup_rmap(ptepage, true);
3901
			set_huge_pte_at(dst, addr, dst_pte, entry);
3902
			hugetlb_count_add(pages_per_huge_page(h), dst);
3903
		}
3904 3905
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3906 3907
	}

3908
	if (cow)
3909
		mmu_notifier_invalidate_range_end(&range);
3910 3911
	else
		i_mmap_unlock_read(mapping);
3912 3913

	return ret;
D
David Gibson 已提交
3914 3915
}

3916 3917 3918
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
3919 3920 3921
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3922
	pte_t *ptep;
D
David Gibson 已提交
3923
	pte_t pte;
3924
	spinlock_t *ptl;
D
David Gibson 已提交
3925
	struct page *page;
3926 3927
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3928
	struct mmu_notifier_range range;
3929

D
David Gibson 已提交
3930
	WARN_ON(!is_vm_hugetlb_page(vma));
3931 3932
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3933

3934 3935 3936 3937
	/*
	 * This is a hugetlb vma, all the pte entries should point
	 * to huge page.
	 */
3938
	tlb_change_page_size(tlb, sz);
3939
	tlb_start_vma(tlb, vma);
3940 3941 3942 3943

	/*
	 * If sharing possible, alert mmu notifiers of worst case.
	 */
3944 3945
	mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
				end);
3946 3947
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
	mmu_notifier_invalidate_range_start(&range);
3948 3949
	address = start;
	for (; address < end; address += sz) {
3950
		ptep = huge_pte_offset(mm, address, sz);
A
Adam Litke 已提交
3951
		if (!ptep)
3952 3953
			continue;

3954
		ptl = huge_pte_lock(h, mm, ptep);
3955
		if (huge_pmd_unshare(mm, vma, &address, ptep)) {
3956
			spin_unlock(ptl);
3957 3958 3959 3960
			/*
			 * We just unmapped a page of PMDs by clearing a PUD.
			 * The caller's TLB flush range should cover this area.
			 */
3961 3962
			continue;
		}
3963

3964
		pte = huge_ptep_get(ptep);
3965 3966 3967 3968
		if (huge_pte_none(pte)) {
			spin_unlock(ptl);
			continue;
		}
3969 3970

		/*
3971 3972
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3973
		 */
3974
		if (unlikely(!pte_present(pte))) {
3975
			huge_pte_clear(mm, address, ptep, sz);
3976 3977
			spin_unlock(ptl);
			continue;
3978
		}
3979 3980

		page = pte_page(pte);
3981 3982 3983 3984 3985 3986
		/*
		 * 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) {
3987 3988 3989 3990
			if (page != ref_page) {
				spin_unlock(ptl);
				continue;
			}
3991 3992 3993 3994 3995 3996 3997 3998
			/*
			 * 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);
		}

3999
		pte = huge_ptep_get_and_clear(mm, address, ptep);
4000
		tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
4001
		if (huge_pte_dirty(pte))
4002
			set_page_dirty(page);
4003

4004
		hugetlb_count_sub(pages_per_huge_page(h), mm);
4005
		page_remove_rmap(page, true);
4006

4007
		spin_unlock(ptl);
4008
		tlb_remove_page_size(tlb, page, huge_page_size(h));
4009 4010 4011 4012 4013
		/*
		 * Bail out after unmapping reference page if supplied
		 */
		if (ref_page)
			break;
4014
	}
4015
	mmu_notifier_invalidate_range_end(&range);
4016
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
4017
}
D
David Gibson 已提交
4018

4019 4020 4021 4022 4023 4024 4025 4026 4027 4028 4029 4030
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
4031
	 * is to clear it before releasing the i_mmap_rwsem. This works
4032
	 * because in the context this is called, the VMA is about to be
4033
	 * destroyed and the i_mmap_rwsem is held.
4034 4035 4036 4037
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

4038
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
4039
			  unsigned long end, struct page *ref_page)
4040
{
4041 4042
	struct mm_struct *mm;
	struct mmu_gather tlb;
4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053
	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);
4054 4055 4056

	mm = vma->vm_mm;

4057
	tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end);
4058
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
4059
	tlb_finish_mmu(&tlb, tlb_start, tlb_end);
4060 4061
}

4062 4063 4064 4065 4066 4067
/*
 * 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.
 */
4068 4069
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
4070
{
4071
	struct hstate *h = hstate_vma(vma);
4072 4073 4074 4075 4076 4077 4078 4079
	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.
	 */
4080
	address = address & huge_page_mask(h);
4081 4082
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
4083
	mapping = vma->vm_file->f_mapping;
4084

4085 4086 4087 4088 4089
	/*
	 * 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
	 */
4090
	i_mmap_lock_write(mapping);
4091
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4092 4093 4094 4095
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

4096 4097 4098 4099 4100 4101 4102 4103
		/*
		 * 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;

4104 4105 4106 4107 4108 4109 4110 4111
		/*
		 * 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))
4112 4113
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
4114
	}
4115
	i_mmap_unlock_write(mapping);
4116 4117
}

4118 4119
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4120 4121 4122
 * 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.
4123
 */
4124
static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4125
		       unsigned long address, pte_t *ptep,
4126
		       struct page *pagecache_page, spinlock_t *ptl)
4127
{
4128
	pte_t pte;
4129
	struct hstate *h = hstate_vma(vma);
4130
	struct page *old_page, *new_page;
4131 4132
	int outside_reserve = 0;
	vm_fault_t ret = 0;
4133
	unsigned long haddr = address & huge_page_mask(h);
4134
	struct mmu_notifier_range range;
4135

4136
	pte = huge_ptep_get(ptep);
4137 4138
	old_page = pte_page(pte);

4139
retry_avoidcopy:
4140 4141
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
4142
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4143
		page_move_anon_rmap(old_page, vma);
4144
		set_huge_ptep_writable(vma, haddr, ptep);
N
Nick Piggin 已提交
4145
		return 0;
4146 4147
	}

4148 4149 4150 4151 4152 4153 4154 4155 4156
	/*
	 * 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.
	 */
4157
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4158 4159 4160
			old_page != pagecache_page)
		outside_reserve = 1;

4161
	get_page(old_page);
4162

4163 4164 4165 4166
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
4167
	spin_unlock(ptl);
4168
	new_page = alloc_huge_page(vma, haddr, outside_reserve);
4169

4170
	if (IS_ERR(new_page)) {
4171 4172 4173 4174 4175 4176 4177 4178
		/*
		 * 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) {
4179 4180 4181 4182
			struct address_space *mapping = vma->vm_file->f_mapping;
			pgoff_t idx;
			u32 hash;

4183
			put_page(old_page);
4184
			BUG_ON(huge_pte_none(pte));
4185 4186 4187 4188 4189 4190 4191 4192 4193 4194 4195 4196 4197 4198
			/*
			 * Drop hugetlb_fault_mutex and i_mmap_rwsem before
			 * unmapping.  unmapping needs to hold i_mmap_rwsem
			 * in write mode.  Dropping i_mmap_rwsem in read mode
			 * here is OK as COW mappings do not interact with
			 * PMD sharing.
			 *
			 * Reacquire both after unmap operation.
			 */
			idx = vma_hugecache_offset(h, vma, haddr);
			hash = hugetlb_fault_mutex_hash(mapping, idx);
			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
			i_mmap_unlock_read(mapping);

4199
			unmap_ref_private(mm, vma, old_page, haddr);
4200 4201 4202

			i_mmap_lock_read(mapping);
			mutex_lock(&hugetlb_fault_mutex_table[hash]);
4203
			spin_lock(ptl);
4204
			ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4205 4206 4207 4208 4209 4210 4211 4212
			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;
4213 4214
		}

4215
		ret = vmf_error(PTR_ERR(new_page));
4216
		goto out_release_old;
4217 4218
	}

4219 4220 4221 4222
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
4223
	if (unlikely(anon_vma_prepare(vma))) {
4224 4225
		ret = VM_FAULT_OOM;
		goto out_release_all;
4226
	}
4227

4228
	copy_user_huge_page(new_page, old_page, address, vma,
A
Andrea Arcangeli 已提交
4229
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
4230
	__SetPageUptodate(new_page);
4231

4232
	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4233
				haddr + huge_page_size(h));
4234
	mmu_notifier_invalidate_range_start(&range);
4235

4236
	/*
4237
	 * Retake the page table lock to check for racing updates
4238 4239
	 * before the page tables are altered
	 */
4240
	spin_lock(ptl);
4241
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4242
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4243 4244
		ClearPagePrivate(new_page);

4245
		/* Break COW */
4246
		huge_ptep_clear_flush(vma, haddr, ptep);
4247
		mmu_notifier_invalidate_range(mm, range.start, range.end);
4248
		set_huge_pte_at(mm, haddr, ptep,
4249
				make_huge_pte(vma, new_page, 1));
4250
		page_remove_rmap(old_page, true);
4251
		hugepage_add_new_anon_rmap(new_page, vma, haddr);
4252
		set_page_huge_active(new_page);
4253 4254 4255
		/* Make the old page be freed below */
		new_page = old_page;
	}
4256
	spin_unlock(ptl);
4257
	mmu_notifier_invalidate_range_end(&range);
4258
out_release_all:
4259
	restore_reserve_on_error(h, vma, haddr, new_page);
4260
	put_page(new_page);
4261
out_release_old:
4262
	put_page(old_page);
4263

4264 4265
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
4266 4267
}

4268
/* Return the pagecache page at a given address within a VMA */
4269 4270
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
4271 4272
{
	struct address_space *mapping;
4273
	pgoff_t idx;
4274 4275

	mapping = vma->vm_file->f_mapping;
4276
	idx = vma_hugecache_offset(h, vma, address);
4277 4278 4279 4280

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
4281 4282 4283 4284 4285
/*
 * 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
4286 4287 4288 4289 4290 4291 4292 4293 4294 4295 4296 4297 4298 4299 4300
			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;
}

4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311
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);

4312 4313 4314 4315 4316 4317
	/*
	 * set page dirty so that it will not be removed from cache/file
	 * by non-hugetlbfs specific code paths.
	 */
	set_page_dirty(page);

4318 4319 4320 4321 4322 4323
	spin_lock(&inode->i_lock);
	inode->i_blocks += blocks_per_huge_page(h);
	spin_unlock(&inode->i_lock);
	return 0;
}

4324 4325 4326 4327
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)
4328
{
4329
	struct hstate *h = hstate_vma(vma);
4330
	vm_fault_t ret = VM_FAULT_SIGBUS;
4331
	int anon_rmap = 0;
A
Adam Litke 已提交
4332 4333
	unsigned long size;
	struct page *page;
4334
	pte_t new_pte;
4335
	spinlock_t *ptl;
4336
	unsigned long haddr = address & huge_page_mask(h);
4337
	bool new_page = false;
A
Adam Litke 已提交
4338

4339 4340 4341
	/*
	 * 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
4342
	 * COW. Warn that such a situation has occurred as it may not be obvious
4343 4344
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4345
		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4346
			   current->pid);
4347 4348 4349
		return ret;
	}

A
Adam Litke 已提交
4350
	/*
4351 4352 4353
	 * 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
4354
	 */
4355 4356 4357 4358
	size = i_size_read(mapping->host) >> huge_page_shift(h);
	if (idx >= size)
		goto out;

4359 4360 4361
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
4362 4363 4364 4365 4366 4367 4368
		/*
		 * Check for page in userfault range
		 */
		if (userfaultfd_missing(vma)) {
			u32 hash;
			struct vm_fault vmf = {
				.vma = vma,
4369
				.address = haddr,
4370 4371 4372 4373 4374 4375 4376 4377 4378 4379 4380
				.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
				 */
			};

			/*
4381 4382 4383
			 * hugetlb_fault_mutex and i_mmap_rwsem must be
			 * dropped before handling userfault.  Reacquire
			 * after handling fault to make calling code simpler.
4384
			 */
4385
			hash = hugetlb_fault_mutex_hash(mapping, idx);
4386
			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4387
			i_mmap_unlock_read(mapping);
4388
			ret = handle_userfault(&vmf, VM_UFFD_MISSING);
4389
			i_mmap_lock_read(mapping);
4390 4391 4392 4393
			mutex_lock(&hugetlb_fault_mutex_table[hash]);
			goto out;
		}

4394
		page = alloc_huge_page(vma, haddr, 0);
4395
		if (IS_ERR(page)) {
4396 4397 4398 4399 4400 4401 4402 4403 4404 4405 4406 4407 4408 4409 4410 4411 4412 4413 4414
			/*
			 * 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);
4415
			ret = vmf_error(PTR_ERR(page));
4416 4417
			goto out;
		}
A
Andrea Arcangeli 已提交
4418
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
4419
		__SetPageUptodate(page);
4420
		new_page = true;
4421

4422
		if (vma->vm_flags & VM_MAYSHARE) {
4423
			int err = huge_add_to_page_cache(page, mapping, idx);
4424 4425 4426 4427 4428 4429
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
4430
		} else {
4431
			lock_page(page);
4432 4433 4434 4435
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
4436
			anon_rmap = 1;
4437
		}
4438
	} else {
4439 4440 4441 4442 4443 4444
		/*
		 * 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))) {
4445
			ret = VM_FAULT_HWPOISON_LARGE |
4446
				VM_FAULT_SET_HINDEX(hstate_index(h));
4447 4448
			goto backout_unlocked;
		}
4449
	}
4450

4451 4452 4453 4454 4455 4456
	/*
	 * 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.
	 */
4457
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4458
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4459 4460 4461
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
4462
		/* Just decrements count, does not deallocate */
4463
		vma_end_reservation(h, vma, haddr);
4464
	}
4465

4466
	ptl = huge_pte_lock(h, mm, ptep);
N
Nick Piggin 已提交
4467
	ret = 0;
4468
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
4469 4470
		goto backout;

4471 4472
	if (anon_rmap) {
		ClearPagePrivate(page);
4473
		hugepage_add_new_anon_rmap(page, vma, haddr);
4474
	} else
4475
		page_dup_rmap(page, true);
4476 4477
	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
				&& (vma->vm_flags & VM_SHARED)));
4478
	set_huge_pte_at(mm, haddr, ptep, new_pte);
4479

4480
	hugetlb_count_add(pages_per_huge_page(h), mm);
4481
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4482
		/* Optimization, do the COW without a second fault */
4483
		ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4484 4485
	}

4486
	spin_unlock(ptl);
4487 4488 4489 4490 4491 4492 4493 4494 4495

	/*
	 * 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
4496 4497
	unlock_page(page);
out:
4498
	return ret;
A
Adam Litke 已提交
4499 4500

backout:
4501
	spin_unlock(ptl);
4502
backout_unlocked:
A
Adam Litke 已提交
4503
	unlock_page(page);
4504
	restore_reserve_on_error(h, vma, haddr, page);
A
Adam Litke 已提交
4505 4506
	put_page(page);
	goto out;
4507 4508
}

4509
#ifdef CONFIG_SMP
4510
u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4511 4512 4513 4514
{
	unsigned long key[2];
	u32 hash;

4515 4516
	key[0] = (unsigned long) mapping;
	key[1] = idx;
4517

4518
	hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4519 4520 4521 4522 4523 4524 4525 4526

	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.
 */
4527
u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4528 4529 4530 4531 4532
{
	return 0;
}
#endif

4533
vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4534
			unsigned long address, unsigned int flags)
4535
{
4536
	pte_t *ptep, entry;
4537
	spinlock_t *ptl;
4538
	vm_fault_t ret;
4539 4540
	u32 hash;
	pgoff_t idx;
4541
	struct page *page = NULL;
4542
	struct page *pagecache_page = NULL;
4543
	struct hstate *h = hstate_vma(vma);
4544
	struct address_space *mapping;
4545
	int need_wait_lock = 0;
4546
	unsigned long haddr = address & huge_page_mask(h);
4547

4548
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4549
	if (ptep) {
4550 4551 4552 4553 4554
		/*
		 * 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.
		 */
4555
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
4556
		if (unlikely(is_hugetlb_entry_migration(entry))) {
4557
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
4558 4559
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4560
			return VM_FAULT_HWPOISON_LARGE |
4561
				VM_FAULT_SET_HINDEX(hstate_index(h));
4562 4563
	}

4564 4565
	/*
	 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4566 4567 4568 4569
	 * 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.
4570 4571 4572 4573 4574
	 *
	 * 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.
	 */
4575
	mapping = vma->vm_file->f_mapping;
4576 4577 4578 4579 4580 4581
	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;
	}
4582

4583 4584 4585 4586 4587
	/*
	 * 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.
	 */
4588
	idx = vma_hugecache_offset(h, vma, haddr);
4589
	hash = hugetlb_fault_mutex_hash(mapping, idx);
4590
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
4591

4592 4593
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
4594
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4595
		goto out_mutex;
4596
	}
4597

N
Nick Piggin 已提交
4598
	ret = 0;
4599

4600 4601 4602
	/*
	 * 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
4603 4604 4605
	 * an active hugepage in pagecache. This goto expects the 2nd page
	 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
	 * properly handle it.
4606 4607 4608 4609
	 */
	if (!pte_present(entry))
		goto out_mutex;

4610 4611 4612 4613 4614 4615 4616 4617
	/*
	 * 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.
	 */
4618
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4619
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4620
			ret = VM_FAULT_OOM;
4621
			goto out_mutex;
4622
		}
4623
		/* Just decrements count, does not deallocate */
4624
		vma_end_reservation(h, vma, haddr);
4625

4626
		if (!(vma->vm_flags & VM_MAYSHARE))
4627
			pagecache_page = hugetlbfs_pagecache_page(h,
4628
								vma, haddr);
4629 4630
	}

4631 4632 4633 4634 4635 4636
	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;

4637 4638 4639 4640 4641 4642 4643
	/*
	 * 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)
4644 4645 4646 4647
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
4648

4649
	get_page(page);
4650

4651
	if (flags & FAULT_FLAG_WRITE) {
4652
		if (!huge_pte_write(entry)) {
4653
			ret = hugetlb_cow(mm, vma, address, ptep,
4654
					  pagecache_page, ptl);
4655
			goto out_put_page;
4656
		}
4657
		entry = huge_pte_mkdirty(entry);
4658 4659
	}
	entry = pte_mkyoung(entry);
4660
	if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4661
						flags & FAULT_FLAG_WRITE))
4662
		update_mmu_cache(vma, haddr, ptep);
4663 4664 4665 4666
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
4667 4668
out_ptl:
	spin_unlock(ptl);
4669 4670 4671 4672 4673

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
4674
out_mutex:
4675
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4676
	i_mmap_unlock_read(mapping);
4677 4678 4679 4680 4681 4682 4683 4684 4685
	/*
	 * 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);
4686
	return ret;
4687 4688
}

4689 4690 4691 4692 4693 4694 4695 4696 4697 4698 4699
/*
 * 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)
{
4700 4701 4702
	struct address_space *mapping;
	pgoff_t idx;
	unsigned long size;
4703
	int vm_shared = dst_vma->vm_flags & VM_SHARED;
4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714 4715 4716 4717
	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,
4718
						pages_per_huge_page(h), false);
4719

4720
		/* fallback to copy_from_user outside mmap_lock */
4721
		if (unlikely(ret)) {
4722
			ret = -ENOENT;
4723 4724 4725 4726 4727 4728 4729 4730 4731 4732 4733 4734 4735 4736 4737 4738
			*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);

4739 4740 4741
	mapping = dst_vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, dst_vma, dst_addr);

4742 4743 4744 4745
	/*
	 * If shared, add to page cache
	 */
	if (vm_shared) {
4746 4747 4748 4749
		size = i_size_read(mapping->host) >> huge_page_shift(h);
		ret = -EFAULT;
		if (idx >= size)
			goto out_release_nounlock;
4750

4751 4752 4753 4754 4755 4756
		/*
		 * 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.
		 */
4757 4758 4759 4760 4761
		ret = huge_add_to_page_cache(page, mapping, idx);
		if (ret)
			goto out_release_nounlock;
	}

4762 4763 4764
	ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
	spin_lock(ptl);

4765 4766 4767 4768 4769 4770 4771 4772 4773 4774 4775 4776 4777 4778
	/*
	 * 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;

4779 4780 4781 4782
	ret = -EEXIST;
	if (!huge_pte_none(huge_ptep_get(dst_pte)))
		goto out_release_unlock;

4783 4784 4785 4786 4787 4788
	if (vm_shared) {
		page_dup_rmap(page, true);
	} else {
		ClearPagePrivate(page);
		hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
	}
4789 4790 4791 4792 4793 4794 4795 4796 4797 4798 4799 4800 4801 4802 4803 4804

	_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);
4805
	set_page_huge_active(page);
4806 4807
	if (vm_shared)
		unlock_page(page);
4808 4809 4810 4811 4812
	ret = 0;
out:
	return ret;
out_release_unlock:
	spin_unlock(ptl);
4813 4814
	if (vm_shared)
		unlock_page(page);
4815
out_release_nounlock:
4816 4817 4818 4819
	put_page(page);
	goto out;
}

4820 4821 4822
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,
4823
			 long i, unsigned int flags, int *locked)
D
David Gibson 已提交
4824
{
4825 4826
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
4827
	unsigned long remainder = *nr_pages;
4828
	struct hstate *h = hstate_vma(vma);
4829
	int err = -EFAULT;
D
David Gibson 已提交
4830 4831

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
4832
		pte_t *pte;
4833
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
4834
		int absent;
A
Adam Litke 已提交
4835
		struct page *page;
D
David Gibson 已提交
4836

4837 4838 4839 4840
		/*
		 * If we have a pending SIGKILL, don't keep faulting pages and
		 * potentially allocating memory.
		 */
4841
		if (fatal_signal_pending(current)) {
4842 4843 4844 4845
			remainder = 0;
			break;
		}

A
Adam Litke 已提交
4846 4847
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
4848
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
4849
		 * first, for the page indexing below to work.
4850 4851
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
4852
		 */
4853 4854
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
				      huge_page_size(h));
4855 4856
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
4857 4858 4859 4860
		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
4861 4862 4863 4864
		 * 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
4865
		 */
H
Hugh Dickins 已提交
4866 4867
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4868 4869
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
4870 4871 4872
			remainder = 0;
			break;
		}
D
David Gibson 已提交
4873

4874 4875 4876 4877 4878 4879 4880 4881 4882 4883 4884
		/*
		 * 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)) ||
4885 4886
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
4887
			vm_fault_t ret;
4888
			unsigned int fault_flags = 0;
D
David Gibson 已提交
4889

4890 4891
			if (pte)
				spin_unlock(ptl);
4892 4893
			if (flags & FOLL_WRITE)
				fault_flags |= FAULT_FLAG_WRITE;
4894
			if (locked)
4895 4896
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_KILLABLE;
4897 4898 4899 4900
			if (flags & FOLL_NOWAIT)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_RETRY_NOWAIT;
			if (flags & FOLL_TRIED) {
4901 4902 4903 4904
				/*
				 * Note: FAULT_FLAG_ALLOW_RETRY and
				 * FAULT_FLAG_TRIED can co-exist
				 */
4905 4906 4907 4908
				fault_flags |= FAULT_FLAG_TRIED;
			}
			ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
			if (ret & VM_FAULT_ERROR) {
4909
				err = vm_fault_to_errno(ret, flags);
4910 4911 4912 4913
				remainder = 0;
				break;
			}
			if (ret & VM_FAULT_RETRY) {
4914
				if (locked &&
4915
				    !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4916
					*locked = 0;
4917 4918 4919 4920 4921 4922 4923 4924 4925 4926 4927 4928 4929
				*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
4930 4931
		}

4932
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4933
		page = pte_page(huge_ptep_get(pte));
4934

4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 4945 4946 4947 4948
		/*
		 * 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;
		}

4949
same_page:
4950
		if (pages) {
H
Hugh Dickins 已提交
4951
			pages[i] = mem_map_offset(page, pfn_offset);
J
John Hubbard 已提交
4952 4953 4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967
			/*
			 * 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;
			}
4968
		}
D
David Gibson 已提交
4969 4970 4971 4972 4973

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
4974
		++pfn_offset;
D
David Gibson 已提交
4975 4976
		--remainder;
		++i;
4977
		if (vaddr < vma->vm_end && remainder &&
4978
				pfn_offset < pages_per_huge_page(h)) {
4979 4980 4981 4982 4983 4984
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
4985
		spin_unlock(ptl);
D
David Gibson 已提交
4986
	}
4987
	*nr_pages = remainder;
4988 4989 4990 4991 4992
	/*
	 * 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
4993 4994
	*position = vaddr;

4995
	return i ? i : err;
D
David Gibson 已提交
4996
}
4997

4998 4999 5000 5001 5002 5003 5004 5005
#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

5006
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
5007 5008 5009 5010 5011 5012
		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;
5013
	struct hstate *h = hstate_vma(vma);
5014
	unsigned long pages = 0;
5015
	bool shared_pmd = false;
5016
	struct mmu_notifier_range range;
5017 5018 5019

	/*
	 * In the case of shared PMDs, the area to flush could be beyond
5020
	 * start/end.  Set range.start/range.end to cover the maximum possible
5021 5022
	 * range if PMD sharing is possible.
	 */
5023 5024
	mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
				0, vma, mm, start, end);
5025
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
5026 5027

	BUG_ON(address >= end);
5028
	flush_cache_range(vma, range.start, range.end);
5029

5030
	mmu_notifier_invalidate_range_start(&range);
5031
	i_mmap_lock_write(vma->vm_file->f_mapping);
5032
	for (; address < end; address += huge_page_size(h)) {
5033
		spinlock_t *ptl;
5034
		ptep = huge_pte_offset(mm, address, huge_page_size(h));
5035 5036
		if (!ptep)
			continue;
5037
		ptl = huge_pte_lock(h, mm, ptep);
5038
		if (huge_pmd_unshare(mm, vma, &address, ptep)) {
5039
			pages++;
5040
			spin_unlock(ptl);
5041
			shared_pmd = true;
5042
			continue;
5043
		}
5044 5045 5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056
		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);
5057 5058
				set_huge_swap_pte_at(mm, address, ptep,
						     newpte, huge_page_size(h));
5059 5060 5061 5062 5063 5064
				pages++;
			}
			spin_unlock(ptl);
			continue;
		}
		if (!huge_pte_none(pte)) {
5065 5066 5067 5068
			pte_t old_pte;

			old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
			pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
5069
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
5070
			huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
5071
			pages++;
5072
		}
5073
		spin_unlock(ptl);
5074
	}
5075
	/*
5076
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
5077
	 * may have cleared our pud entry and done put_page on the page table:
5078
	 * once we release i_mmap_rwsem, another task can do the final put_page
5079 5080
	 * 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.
5081
	 */
5082
	if (shared_pmd)
5083
		flush_hugetlb_tlb_range(vma, range.start, range.end);
5084 5085
	else
		flush_hugetlb_tlb_range(vma, start, end);
5086 5087 5088 5089
	/*
	 * No need to call mmu_notifier_invalidate_range() we are downgrading
	 * page table protection not changing it to point to a new page.
	 *
5090
	 * See Documentation/vm/mmu_notifier.rst
5091
	 */
5092
	i_mmap_unlock_write(vma->vm_file->f_mapping);
5093
	mmu_notifier_invalidate_range_end(&range);
5094 5095

	return pages << h->order;
5096 5097
}

5098 5099
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
5100
					struct vm_area_struct *vma,
5101
					vm_flags_t vm_flags)
5102
{
5103
	long ret, chg, add = -1;
5104
	struct hstate *h = hstate_inode(inode);
5105
	struct hugepage_subpool *spool = subpool_inode(inode);
5106
	struct resv_map *resv_map;
5107
	struct hugetlb_cgroup *h_cg = NULL;
5108
	long gbl_reserve, regions_needed = 0;
5109

5110 5111 5112 5113 5114 5115
	/* This should never happen */
	if (from > to) {
		VM_WARN(1, "%s called with a negative range\n", __func__);
		return -EINVAL;
	}

5116 5117 5118
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
5119
	 * without using reserves
5120
	 */
5121
	if (vm_flags & VM_NORESERVE)
5122 5123
		return 0;

5124 5125 5126 5127 5128 5129
	/*
	 * 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
	 */
5130
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
5131 5132 5133 5134 5135
		/*
		 * 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).
		 */
5136
		resv_map = inode_resv_map(inode);
5137

5138
		chg = region_chg(resv_map, from, to, &regions_needed);
5139 5140

	} else {
5141
		/* Private mapping. */
5142
		resv_map = resv_map_alloc();
5143 5144 5145
		if (!resv_map)
			return -ENOMEM;

5146
		chg = to - from;
5147

5148 5149 5150 5151
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

5152 5153 5154 5155
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
5156

5157 5158 5159 5160 5161 5162 5163 5164 5165 5166 5167 5168 5169 5170 5171
	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);
	}

5172 5173 5174 5175 5176 5177 5178
	/*
	 * 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) {
5179
		ret = -ENOSPC;
5180
		goto out_uncharge_cgroup;
5181
	}
5182 5183

	/*
5184
	 * Check enough hugepages are available for the reservation.
5185
	 * Hand the pages back to the subpool if there are not
5186
	 */
5187
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
5188
	if (ret < 0) {
5189
		goto out_put_pages;
K
Ken Chen 已提交
5190
	}
5191 5192 5193 5194 5195 5196 5197 5198 5199 5200 5201 5202

	/*
	 * 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
	 */
5203
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
5204
		add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5205 5206 5207

		if (unlikely(add < 0)) {
			hugetlb_acct_memory(h, -gbl_reserve);
5208
			ret = add;
5209
			goto out_put_pages;
5210
		} else if (unlikely(chg > add)) {
5211 5212 5213 5214 5215 5216 5217 5218 5219
			/*
			 * 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;

5220 5221 5222 5223
			/*
			 * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
			 * reference to h_cg->css. See comment below for detail.
			 */
5224 5225 5226 5227
			hugetlb_cgroup_uncharge_cgroup_rsvd(
				hstate_index(h),
				(chg - add) * pages_per_huge_page(h), h_cg);

5228 5229 5230
			rsv_adjust = hugepage_subpool_put_pages(spool,
								chg - add);
			hugetlb_acct_memory(h, -rsv_adjust);
5231 5232 5233 5234 5235 5236 5237 5238
		} else if (h_cg) {
			/*
			 * The file_regions will hold their own reference to
			 * h_cg->css. So we should release the reference held
			 * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
			 * done.
			 */
			hugetlb_cgroup_put_rsvd_cgroup(h_cg);
5239 5240
		}
	}
5241
	return 0;
5242 5243 5244 5245 5246 5247
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);
5248
out_err:
5249
	if (!vma || vma->vm_flags & VM_MAYSHARE)
5250 5251 5252 5253 5254
		/* 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
5255 5256
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
5257
	return ret;
5258 5259
}

5260 5261
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
5262
{
5263
	struct hstate *h = hstate_inode(inode);
5264
	struct resv_map *resv_map = inode_resv_map(inode);
5265
	long chg = 0;
5266
	struct hugepage_subpool *spool = subpool_inode(inode);
5267
	long gbl_reserve;
K
Ken Chen 已提交
5268

5269 5270 5271 5272
	/*
	 * Since this routine can be called in the evict inode path for all
	 * hugetlbfs inodes, resv_map could be NULL.
	 */
5273 5274 5275 5276 5277 5278 5279 5280 5281 5282 5283
	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
5284
	spin_lock(&inode->i_lock);
5285
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
5286 5287
	spin_unlock(&inode->i_lock);

5288 5289 5290 5291 5292 5293
	/*
	 * 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);
5294 5295

	return 0;
5296
}
5297

5298 5299 5300 5301 5302 5303 5304 5305 5306 5307 5308
#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
5309 5310
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5311 5312 5313 5314 5315 5316 5317 5318 5319 5320 5321 5322 5323

	/*
	 * 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;
}

5324
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5325 5326 5327 5328 5329 5330 5331
{
	unsigned long base = addr & PUD_MASK;
	unsigned long end = base + PUD_SIZE;

	/*
	 * check on proper vm_flags and page table alignment
	 */
5332
	if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5333 5334
		return true;
	return false;
5335 5336
}

5337 5338 5339 5340 5341 5342 5343 5344
/*
 * 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)
{
5345 5346
	unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
		v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
5347

5348 5349 5350 5351 5352 5353
	/*
	 * vma need span at least one aligned PUD size and the start,end range
	 * must at least partialy within it.
	 */
	if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
		(*end <= v_start) || (*start >= v_end))
5354 5355
		return;

5356
	/* Extend the range to be PUD aligned for a worst case scenario */
5357 5358
	if (*start > v_start)
		*start = ALIGN_DOWN(*start, PUD_SIZE);
5359

5360 5361
	if (*end < v_end)
		*end = ALIGN(*end, PUD_SIZE);
5362 5363
}

5364 5365 5366 5367
/*
 * 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
5368 5369
 * code much cleaner.
 *
5370 5371 5372 5373 5374 5375 5376 5377 5378 5379
 * This routine must be called with i_mmap_rwsem held in at least read mode if
 * sharing is possible.  For hugetlbfs, this prevents removal of any page
 * table entries associated with the address space.  This is important as we
 * are setting up sharing based on existing page table entries (mappings).
 *
 * NOTE: This routine is only called from huge_pte_alloc.  Some callers of
 * huge_pte_alloc know that sharing is not possible and do not take
 * i_mmap_rwsem as a performance optimization.  This is handled by the
 * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
 * only required for subsequent processing.
5380 5381 5382 5383 5384 5385 5386 5387 5388 5389 5390
 */
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;
5391
	spinlock_t *ptl;
5392 5393 5394 5395

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

5396
	i_mmap_assert_locked(mapping);
5397 5398 5399 5400 5401 5402
	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

		saddr = page_table_shareable(svma, vma, addr, idx);
		if (saddr) {
5403 5404
			spte = huge_pte_offset(svma->vm_mm, saddr,
					       vma_mmu_pagesize(svma));
5405 5406 5407 5408 5409 5410 5411 5412 5413 5414
			if (spte) {
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

5415
	ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5416
	if (pud_none(*pud)) {
5417 5418
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
5419
		mm_inc_nr_pmds(mm);
5420
	} else {
5421
		put_page(virt_to_page(spte));
5422
	}
5423
	spin_unlock(ptl);
5424 5425 5426 5427 5428 5429 5430 5431 5432 5433 5434 5435
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.
 *
5436
 * Called with page table lock held and i_mmap_rwsem held in write mode.
5437 5438 5439 5440
 *
 * returns: 1 successfully unmapped a shared pte page
 *	    0 the underlying pte page is not shared, or it is the last user
 */
5441 5442
int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
					unsigned long *addr, pte_t *ptep)
5443 5444
{
	pgd_t *pgd = pgd_offset(mm, *addr);
5445 5446
	p4d_t *p4d = p4d_offset(pgd, *addr);
	pud_t *pud = pud_offset(p4d, *addr);
5447

5448
	i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5449 5450 5451 5452 5453 5454
	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));
5455
	mm_dec_nr_pmds(mm);
5456 5457 5458
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
5459 5460 5461 5462 5463 5464
#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;
}
5465

5466 5467
int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
				unsigned long *addr, pte_t *ptep)
5468 5469 5470
{
	return 0;
}
5471 5472 5473 5474 5475

void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
				unsigned long *start, unsigned long *end)
{
}
5476
#define want_pmd_share()	(0)
5477 5478
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

5479 5480 5481 5482 5483
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
5484
	p4d_t *p4d;
5485 5486 5487 5488
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
5489 5490 5491
	p4d = p4d_alloc(mm, pgd, addr);
	if (!p4d)
		return NULL;
5492
	pud = pud_alloc(mm, p4d, addr);
5493 5494 5495 5496 5497 5498 5499 5500 5501 5502 5503
	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);
		}
	}
5504
	BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5505 5506 5507 5508

	return pte;
}

5509 5510 5511 5512
/*
 * huge_pte_offset() - Walk the page table to resolve the hugepage
 * entry at address @addr
 *
5513 5514
 * Return: Pointer to page table entry (PUD or PMD) for
 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5515 5516 5517
 * size @sz doesn't match the hugepage size at this level of the page
 * table.
 */
5518 5519
pte_t *huge_pte_offset(struct mm_struct *mm,
		       unsigned long addr, unsigned long sz)
5520 5521
{
	pgd_t *pgd;
5522
	p4d_t *p4d;
5523 5524
	pud_t *pud;
	pmd_t *pmd;
5525 5526

	pgd = pgd_offset(mm, addr);
5527 5528 5529 5530 5531
	if (!pgd_present(*pgd))
		return NULL;
	p4d = p4d_offset(pgd, addr);
	if (!p4d_present(*p4d))
		return NULL;
5532

5533
	pud = pud_offset(p4d, addr);
5534 5535
	if (sz == PUD_SIZE)
		/* must be pud huge, non-present or none */
5536
		return (pte_t *)pud;
5537
	if (!pud_present(*pud))
5538
		return NULL;
5539
	/* must have a valid entry and size to go further */
5540

5541 5542 5543
	pmd = pmd_offset(pud, addr);
	/* must be pmd huge, non-present or none */
	return (pte_t *)pmd;
5544 5545
}

5546 5547 5548 5549 5550 5551 5552 5553 5554 5555 5556 5557 5558
#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);
}

5559 5560 5561 5562 5563 5564 5565 5566
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;
}

5567
struct page * __weak
5568
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5569
		pmd_t *pmd, int flags)
5570
{
5571 5572
	struct page *page = NULL;
	spinlock_t *ptl;
5573
	pte_t pte;
J
John Hubbard 已提交
5574 5575 5576 5577 5578 5579

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

5580 5581 5582 5583 5584 5585 5586 5587 5588
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;
5589 5590
	pte = huge_ptep_get((pte_t *)pmd);
	if (pte_present(pte)) {
5591
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
J
John Hubbard 已提交
5592 5593 5594 5595 5596 5597 5598 5599 5600 5601 5602 5603
		/*
		 * 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;
		}
5604
	} else {
5605
		if (is_hugetlb_entry_migration(pte)) {
5606 5607 5608 5609 5610 5611 5612 5613 5614 5615 5616
			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);
5617 5618 5619
	return page;
}

5620
struct page * __weak
5621
follow_huge_pud(struct mm_struct *mm, unsigned long address,
5622
		pud_t *pud, int flags)
5623
{
J
John Hubbard 已提交
5624
	if (flags & (FOLL_GET | FOLL_PIN))
5625
		return NULL;
5626

5627
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5628 5629
}

5630 5631 5632
struct page * __weak
follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
{
J
John Hubbard 已提交
5633
	if (flags & (FOLL_GET | FOLL_PIN))
5634 5635 5636 5637 5638
		return NULL;

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

5639 5640
bool isolate_huge_page(struct page *page, struct list_head *list)
{
5641 5642
	bool ret = true;

5643
	spin_lock(&hugetlb_lock);
5644 5645
	if (!PageHeadHuge(page) || !page_huge_active(page) ||
	    !get_page_unless_zero(page)) {
5646 5647 5648 5649
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
5650
	list_move_tail(&page->lru, list);
5651
unlock:
5652
	spin_unlock(&hugetlb_lock);
5653
	return ret;
5654 5655 5656 5657
}

void putback_active_hugepage(struct page *page)
{
5658
	VM_BUG_ON_PAGE(!PageHead(page), page);
5659
	spin_lock(&hugetlb_lock);
5660
	set_page_huge_active(page);
5661 5662 5663 5664
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}
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

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);
	}
}
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#ifdef CONFIG_CMA
static bool cma_reserve_called __initdata;

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

early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);

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

	cma_reserve_called = true;

	if (!hugetlb_cma_size)
		return;

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

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

	reserved = 0;
	for_each_node_state(nid, N_ONLINE) {
		int res;
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		char name[CMA_MAX_NAME];
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		size = min(per_node, hugetlb_cma_size - reserved);
		size = round_up(size, PAGE_SIZE << order);

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

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

		if (reserved >= hugetlb_cma_size)
			break;
	}
}

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

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

#endif /* CONFIG_CMA */