hugetlb.c 154.5 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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/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);

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

	spin_unlock(&spool->lock);

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	VM_BUG_ON(resv->region_cache_count <= 0);

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

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

	return nrg;
}

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

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

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

#else
	return true;
#endif
}

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

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

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

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		rg = prg;
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	}

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

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

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

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

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

		last_accounted_offset = rg->to;
	}

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

	VM_BUG_ON(add < 0);
	return add;
}

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

	VM_BUG_ON(regions_needed < 0);

	INIT_LIST_HEAD(&allocated_regions);

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

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

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

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		spin_lock(&resv->lock);

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

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

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

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

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

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

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

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

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

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

628 629 630 631 632 633 634 635 636 637 638 639 640
		if (f > rg->from && t < rg->to) { /* Must split region */
			/*
			 * Check for an entry in the cache before dropping
			 * lock and attempting allocation.
			 */
			if (!nrg &&
			    resv->region_cache_count > resv->adds_in_progress) {
				nrg = list_first_entry(&resv->region_cache,
							struct file_region,
							link);
				list_del(&nrg->link);
				resv->region_cache_count--;
			}
641

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

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

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

			copy_hugetlb_cgroup_uncharge_info(nrg, rg);

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

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

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

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

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

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

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

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

699 700 701 702 703 704 705 706 707
/*
 * A rare out of memory error was encountered which prevented removal of
 * the reserve map region for a page.  The huge page itself was free'ed
 * and removed from the page cache.  This routine will adjust the subpool
 * usage count, and the global reserve count if needed.  By incrementing
 * these counts, the reserve map entry which could not be deleted will
 * appear as a "reserved" entry instead of simply dangling with incorrect
 * counts.
 */
708
void hugetlb_fix_reserve_counts(struct inode *inode)
709 710 711 712 713
{
	struct hugepage_subpool *spool = subpool_inode(inode);
	long rsv_adjust;

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

		hugetlb_acct_memory(h, 1);
	}
}

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

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

		if (rg->to <= f)
			continue;
		if (rg->from >= t)
			break;

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

		chg += seg_to - seg_from;
	}
747
	spin_unlock(&resv->lock);
748 749 750 751

	return chg;
}

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

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

770 771 772 773 774 775
/*
 * Return the size of the pages allocated when backing a VMA. In the majority
 * cases this will be same size as used by the page table entries.
 */
unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
{
776 777 778
	if (vma->vm_ops && vma->vm_ops->pagesize)
		return vma->vm_ops->pagesize(vma);
	return PAGE_SIZE;
779
}
780
EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
781

782 783 784
/*
 * Return the page size being used by the MMU to back a VMA. In the majority
 * of cases, the page size used by the kernel matches the MMU size. On
785 786
 * architectures where it differs, an architecture-specific 'strong'
 * version of this symbol is required.
787
 */
788
__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
789 790 791 792
{
	return vma_kernel_pagesize(vma);
}

793 794 795 796 797 798 799
/*
 * Flags for MAP_PRIVATE reservations.  These are stored in the bottom
 * bits of the reservation map pointer, which are always clear due to
 * alignment.
 */
#define HPAGE_RESV_OWNER    (1UL << 0)
#define HPAGE_RESV_UNMAPPED (1UL << 1)
800
#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
801

802 803 804 805 806 807 808 809 810
/*
 * These helpers are used to track how many pages are reserved for
 * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
 * is guaranteed to have their future faults succeed.
 *
 * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
 * the reserve counters are updated with the hugetlb_lock held. It is safe
 * to reset the VMA at fork() time as it is not in use yet and there is no
 * chance of the global counters getting corrupted as a result of the values.
811 812 813 814 815 816 817 818 819
 *
 * The private mapping reservation is represented in a subtly different
 * manner to a shared mapping.  A shared mapping has a region map associated
 * with the underlying file, this region map represents the backing file
 * pages which have ever had a reservation assigned which this persists even
 * after the page is instantiated.  A private mapping has a region map
 * associated with the original mmap which is attached to all VMAs which
 * reference it, this region map represents those offsets which have consumed
 * reservation ie. where pages have been instantiated.
820
 */
821 822 823 824 825 826 827 828 829 830 831
static unsigned long get_vma_private_data(struct vm_area_struct *vma)
{
	return (unsigned long)vma->vm_private_data;
}

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

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

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

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

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

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

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

879 880 881
	return resv_map;
}

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

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

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

	VM_BUG_ON(resv_map->adds_in_progress);

899 900 901
	kfree(resv_map);
}

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

915
static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
916
{
917
	VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
918 919 920 921 922 923 924
	if (vma->vm_flags & VM_MAYSHARE) {
		struct address_space *mapping = vma->vm_file->f_mapping;
		struct inode *inode = mapping->host;

		return inode_resv_map(inode);

	} else {
925 926
		return (struct resv_map *)(get_vma_private_data(vma) &
							~HPAGE_RESV_MASK);
927
	}
928 929
}

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

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

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

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

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

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

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

/* Returns true if the VMA has associated reserve pages */
963
static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
964
{
965 966 967 968 969 970 971 972 973 974 975
	if (vma->vm_flags & VM_NORESERVE) {
		/*
		 * This address is already reserved by other process(chg == 0),
		 * so, we should decrement reserved count. Without decrementing,
		 * reserve count remains after releasing inode, because this
		 * allocated page will go into page cache and is regarded as
		 * coming from reserved pool in releasing step.  Currently, we
		 * don't have any other solution to deal with this situation
		 * properly, so add work-around here.
		 */
		if (vma->vm_flags & VM_MAYSHARE && chg == 0)
976
			return true;
977
		else
978
			return false;
979
	}
980 981

	/* Shared mappings always use reserves */
982 983 984 985 986
	if (vma->vm_flags & VM_MAYSHARE) {
		/*
		 * We know VM_NORESERVE is not set.  Therefore, there SHOULD
		 * be a region map for all pages.  The only situation where
		 * there is no region map is if a hole was punched via
E
Ethon Paul 已提交
987
		 * fallocate.  In this case, there really are no reserves to
988 989 990 991 992 993 994
		 * use.  This situation is indicated if chg != 0.
		 */
		if (chg)
			return false;
		else
			return true;
	}
995 996 997 998 999

	/*
	 * Only the process that called mmap() has reserves for
	 * private mappings.
	 */
1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
		/*
		 * Like the shared case above, a hole punch or truncate
		 * could have been performed on the private mapping.
		 * Examine the value of chg to determine if reserves
		 * actually exist or were previously consumed.
		 * Very Subtle - The value of chg comes from a previous
		 * call to vma_needs_reserves().  The reserve map for
		 * private mappings has different (opposite) semantics
		 * than that of shared mappings.  vma_needs_reserves()
		 * has already taken this difference in semantics into
		 * account.  Therefore, the meaning of chg is the same
		 * as in the shared case above.  Code could easily be
		 * combined, but keeping it separate draws attention to
		 * subtle differences.
		 */
		if (chg)
			return false;
		else
			return true;
	}
1021

1022
	return false;
1023 1024
}

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

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

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

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

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

1052
	return NULL;
1053 1054
}

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

1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079
	zonelist = node_zonelist(nid, gfp_mask);

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

		if (!cpuset_zone_allowed(zone, gfp_mask))
			continue;
		/*
		 * no need to ask again on the same node. Pool is node rather than
		 * zone aware
		 */
		if (zone_to_nid(zone) == node)
			continue;
		node = zone_to_nid(zone);
1080 1081 1082 1083 1084

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

1088 1089 1090
	return NULL;
}

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

1102 1103 1104 1105 1106
	/*
	 * A child process with MAP_PRIVATE mappings created by their parent
	 * have no page reserves. This check ensures that reservations are
	 * not "stolen". The child may still get SIGKILLed
	 */
1107
	if (!vma_has_reserves(vma, chg) &&
1108
			h->free_huge_pages - h->resv_huge_pages == 0)
1109
		goto err;
1110

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

1115 1116
	gfp_mask = htlb_alloc_mask(h);
	nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
1117 1118 1119 1120
	page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
	if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
		SetPagePrivate(page);
		h->resv_huge_pages--;
L
Linus Torvalds 已提交
1121
	}
1122

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

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

1130 1131 1132 1133 1134 1135 1136 1137 1138
/*
 * common helper functions for hstate_next_node_to_{alloc|free}.
 * We may have allocated or freed a huge page based on a different
 * nodes_allowed previously, so h->next_node_to_{alloc|free} might
 * be outside of *nodes_allowed.  Ensure that we use an allowed
 * node for alloc or free.
 */
static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
{
1139
	nid = next_node_in(nid, *nodes_allowed);
1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200
	VM_BUG_ON(nid >= MAX_NUMNODES);

	return nid;
}

static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
{
	if (!node_isset(nid, *nodes_allowed))
		nid = next_node_allowed(nid, nodes_allowed);
	return nid;
}

/*
 * returns the previously saved node ["this node"] from which to
 * allocate a persistent huge page for the pool and advance the
 * next node from which to allocate, handling wrap at end of node
 * mask.
 */
static int hstate_next_node_to_alloc(struct hstate *h,
					nodemask_t *nodes_allowed)
{
	int nid;

	VM_BUG_ON(!nodes_allowed);

	nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
	h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);

	return nid;
}

/*
 * helper for free_pool_huge_page() - return the previously saved
 * node ["this node"] from which to free a huge page.  Advance the
 * next node id whether or not we find a free huge page to free so
 * that the next attempt to free addresses the next node.
 */
static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
{
	int nid;

	VM_BUG_ON(!nodes_allowed);

	nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
	h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);

	return nid;
}

#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask)		\
	for (nr_nodes = nodes_weight(*mask);				\
		nr_nodes > 0 &&						\
		((node = hstate_next_node_to_alloc(hs, mask)) || 1);	\
		nr_nodes--)

#define for_each_node_mask_to_free(hs, nr_nodes, node, mask)		\
	for (nr_nodes = nodes_weight(*mask);				\
		nr_nodes > 0 &&						\
		((node = hstate_next_node_to_free(hs, mask)) || 1);	\
		nr_nodes--)

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

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

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

	set_compound_order(page, 0);
1219
	page[1].compound_nr = 0;
1220 1221 1222
	__ClearPageHead(page);
}

1223
static void free_gigantic_page(struct page *page, unsigned int order)
1224
{
1225 1226 1227 1228
	/*
	 * If the page isn't allocated using the cma allocator,
	 * cma_release() returns false.
	 */
1229 1230
#ifdef CONFIG_CMA
	if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
1231
		return;
1232
#endif
1233

1234 1235 1236
	free_contig_range(page_to_pfn(page), 1 << order);
}

1237
#ifdef CONFIG_CONTIG_ALLOC
1238 1239
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
		int nid, nodemask_t *nodemask)
1240
{
1241
	unsigned long nr_pages = 1UL << huge_page_order(h);
1242 1243
	if (nid == NUMA_NO_NODE)
		nid = numa_mem_id();
1244

1245 1246
#ifdef CONFIG_CMA
	{
1247 1248 1249
		struct page *page;
		int node;

1250 1251 1252
		if (hugetlb_cma[nid]) {
			page = cma_alloc(hugetlb_cma[nid], nr_pages,
					huge_page_order(h), true);
1253 1254 1255
			if (page)
				return page;
		}
1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267

		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;
			}
		}
1268
	}
1269
#endif
1270

1271
	return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
1272 1273 1274
}

static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
1275
static void prep_compound_gigantic_page(struct page *page, unsigned int order);
1276 1277 1278 1279 1280 1281 1282
#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 */
1283

1284
#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
1285
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
1286 1287 1288 1289
					int nid, nodemask_t *nodemask)
{
	return NULL;
}
1290
static inline void free_gigantic_page(struct page *page, unsigned int order) { }
1291
static inline void destroy_compound_gigantic_page(struct page *page,
1292
						unsigned int order) { }
1293 1294
#endif

1295
static void update_and_free_page(struct hstate *h, struct page *page)
A
Adam Litke 已提交
1296 1297
{
	int i;
1298

1299
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
1300
		return;
1301

1302 1303 1304
	h->nr_huge_pages--;
	h->nr_huge_pages_node[page_to_nid(page)]--;
	for (i = 0; i < pages_per_huge_page(h); i++) {
1305 1306
		page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
				1 << PG_referenced | 1 << PG_dirty |
1307 1308
				1 << PG_active | 1 << PG_private |
				1 << PG_writeback);
A
Adam Litke 已提交
1309
	}
1310
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
1311
	VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
1312
	set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
A
Adam Litke 已提交
1313
	set_page_refcounted(page);
1314
	if (hstate_is_gigantic(h)) {
1315 1316 1317 1318 1319
		/*
		 * Temporarily drop the hugetlb_lock, because
		 * we might block in free_gigantic_page().
		 */
		spin_unlock(&hugetlb_lock);
1320 1321
		destroy_compound_gigantic_page(page, huge_page_order(h));
		free_gigantic_page(page, huge_page_order(h));
1322
		spin_lock(&hugetlb_lock);
1323 1324 1325
	} else {
		__free_pages(page, huge_page_order(h));
	}
A
Adam Litke 已提交
1326 1327
}

1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338
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;
}

1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363
/*
 * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
 * to hstate->hugepage_activelist.)
 *
 * This function can be called for tail pages, but never returns true for them.
 */
bool page_huge_active(struct page *page)
{
	VM_BUG_ON_PAGE(!PageHuge(page), page);
	return PageHead(page) && PagePrivate(&page[1]);
}

/* never called for tail page */
static void set_page_huge_active(struct page *page)
{
	VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
	SetPagePrivate(&page[1]);
}

static void clear_page_huge_active(struct page *page)
{
	VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
	ClearPagePrivate(&page[1]);
}

1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385
/*
 * 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;
}

1386
static void __free_huge_page(struct page *page)
1387
{
1388 1389 1390 1391
	/*
	 * Can't pass hstate in here because it is called from the
	 * compound page destructor.
	 */
1392
	struct hstate *h = page_hstate(page);
1393
	int nid = page_to_nid(page);
1394 1395
	struct hugepage_subpool *spool =
		(struct hugepage_subpool *)page_private(page);
1396
	bool restore_reserve;
1397

1398 1399
	VM_BUG_ON_PAGE(page_count(page), page);
	VM_BUG_ON_PAGE(page_mapcount(page), page);
1400 1401 1402

	set_page_private(page, 0);
	page->mapping = NULL;
1403
	restore_reserve = PagePrivate(page);
1404
	ClearPagePrivate(page);
1405

1406
	/*
1407 1408 1409 1410 1411 1412
	 * 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.
1413
	 */
1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
	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;
	}
1424

1425
	spin_lock(&hugetlb_lock);
1426
	clear_page_huge_active(page);
1427 1428
	hugetlb_cgroup_uncharge_page(hstate_index(h),
				     pages_per_huge_page(h), page);
1429 1430
	hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
					  pages_per_huge_page(h), page);
1431 1432 1433
	if (restore_reserve)
		h->resv_huge_pages++;

1434 1435 1436 1437 1438
	if (PageHugeTemporary(page)) {
		list_del(&page->lru);
		ClearPageHugeTemporary(page);
		update_and_free_page(h, page);
	} else if (h->surplus_huge_pages_node[nid]) {
1439 1440
		/* remove the page from active list */
		list_del(&page->lru);
1441 1442 1443
		update_and_free_page(h, page);
		h->surplus_huge_pages--;
		h->surplus_huge_pages_node[nid]--;
1444
	} else {
1445
		arch_clear_hugepage_flags(page);
1446
		enqueue_huge_page(h, page);
1447
	}
1448 1449 1450
	spin_unlock(&hugetlb_lock);
}

1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498
/*
 * 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);
}

1499
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
1500
{
1501
	INIT_LIST_HEAD(&page->lru);
1502
	set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
1503
	set_hugetlb_cgroup(page, NULL);
1504
	set_hugetlb_cgroup_rsvd(page, NULL);
1505
	spin_lock(&hugetlb_lock);
1506 1507
	h->nr_huge_pages++;
	h->nr_huge_pages_node[nid]++;
1508 1509 1510
	spin_unlock(&hugetlb_lock);
}

1511
static void prep_compound_gigantic_page(struct page *page, unsigned int order)
1512 1513 1514 1515 1516 1517 1518
{
	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);
1519
	__ClearPageReserved(page);
1520
	__SetPageHead(page);
1521
	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
1522 1523 1524 1525
		/*
		 * 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
1526
		 * too.  Otherwise drivers using get_user_pages() to access tail
1527 1528 1529 1530 1531 1532 1533 1534
		 * 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);
1535
		set_page_count(p, 0);
1536
		set_compound_head(p, page);
1537
	}
1538
	atomic_set(compound_mapcount_ptr(page), -1);
1539 1540 1541

	if (hpage_pincount_available(page))
		atomic_set(compound_pincount_ptr(page), 0);
1542 1543
}

A
Andrew Morton 已提交
1544 1545 1546 1547 1548
/*
 * PageHuge() only returns true for hugetlbfs pages, but not for normal or
 * transparent huge pages.  See the PageTransHuge() documentation for more
 * details.
 */
1549 1550 1551 1552 1553 1554
int PageHuge(struct page *page)
{
	if (!PageCompound(page))
		return 0;

	page = compound_head(page);
1555
	return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
1556
}
1557 1558
EXPORT_SYMBOL_GPL(PageHuge);

1559 1560 1561 1562 1563 1564 1565 1566 1567
/*
 * 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;

1568
	return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
1569 1570
}

1571 1572 1573
/*
 * Find and lock address space (mapping) in write mode.
 *
1574 1575 1576
 * 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.
1577 1578 1579
 */
struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
{
1580
	struct address_space *mapping = page_mapping(hpage);
1581 1582 1583 1584 1585 1586 1587

	if (!mapping)
		return mapping;

	if (i_mmap_trylock_write(mapping))
		return mapping;

1588
	return NULL;
1589 1590
}

1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607
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;
}

1608
static struct page *alloc_buddy_huge_page(struct hstate *h,
1609 1610
		gfp_t gfp_mask, int nid, nodemask_t *nmask,
		nodemask_t *node_alloc_noretry)
L
Linus Torvalds 已提交
1611
{
1612
	int order = huge_page_order(h);
L
Linus Torvalds 已提交
1613
	struct page *page;
1614
	bool alloc_try_hard = true;
1615

1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627
	/*
	 * 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;
1628 1629 1630 1631 1632 1633 1634
	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);
1635

1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651
	/*
	 * 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);

1652 1653 1654
	return page;
}

1655 1656 1657 1658 1659
/*
 * 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,
1660 1661
		gfp_t gfp_mask, int nid, nodemask_t *nmask,
		nodemask_t *node_alloc_noretry)
1662 1663 1664 1665 1666 1667 1668
{
	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,
1669
				nid, nmask, node_alloc_noretry);
1670 1671 1672 1673 1674 1675 1676 1677 1678 1679
	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;
}

1680 1681 1682 1683
/*
 * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
 * manner.
 */
1684 1685
static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
				nodemask_t *node_alloc_noretry)
1686 1687 1688
{
	struct page *page;
	int nr_nodes, node;
1689
	gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
1690 1691

	for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
1692 1693
		page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
						node_alloc_noretry);
1694
		if (page)
1695 1696 1697
			break;
	}

1698 1699
	if (!page)
		return 0;
1700

1701 1702 1703
	put_page(page); /* free it into the hugepage allocator */

	return 1;
1704 1705
}

1706 1707 1708 1709 1710 1711
/*
 * 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.
 */
1712 1713
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
							 bool acct_surplus)
1714
{
1715
	int nr_nodes, node;
1716 1717
	int ret = 0;

1718
	for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
1719 1720 1721 1722
		/*
		 * If we're returning unused surplus pages, only examine
		 * nodes with surplus pages.
		 */
1723 1724
		if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
		    !list_empty(&h->hugepage_freelists[node])) {
1725
			struct page *page =
1726
				list_entry(h->hugepage_freelists[node].next,
1727 1728 1729
					  struct page, lru);
			list_del(&page->lru);
			h->free_huge_pages--;
1730
			h->free_huge_pages_node[node]--;
1731 1732
			if (acct_surplus) {
				h->surplus_huge_pages--;
1733
				h->surplus_huge_pages_node[node]--;
1734
			}
1735 1736
			update_and_free_page(h, page);
			ret = 1;
1737
			break;
1738
		}
1739
	}
1740 1741 1742 1743

	return ret;
}

1744 1745
/*
 * Dissolve a given free hugepage into free buddy pages. This function does
1746 1747 1748 1749 1750 1751 1752
 * 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)
1753
 */
1754
int dissolve_free_huge_page(struct page *page)
1755
{
1756
	int rc = -EBUSY;
1757

1758 1759 1760 1761
	/* Not to disrupt normal path by vainly holding hugetlb_lock */
	if (!PageHuge(page))
		return 0;

1762
	spin_lock(&hugetlb_lock);
1763 1764 1765 1766 1767 1768
	if (!PageHuge(page)) {
		rc = 0;
		goto out;
	}

	if (!page_count(page)) {
1769 1770 1771
		struct page *head = compound_head(page);
		struct hstate *h = page_hstate(head);
		int nid = page_to_nid(head);
1772
		if (h->free_huge_pages - h->resv_huge_pages == 0)
1773
			goto out;
1774 1775 1776 1777 1778 1779 1780 1781
		/*
		 * 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);
		}
1782
		list_del(&head->lru);
1783 1784
		h->free_huge_pages--;
		h->free_huge_pages_node[nid]--;
1785
		h->max_huge_pages--;
1786
		update_and_free_page(h, head);
1787
		rc = 0;
1788
	}
1789
out:
1790
	spin_unlock(&hugetlb_lock);
1791
	return rc;
1792 1793 1794 1795 1796
}

/*
 * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
 * make specified memory blocks removable from the system.
1797 1798
 * Note that this will dissolve a free gigantic hugepage completely, if any
 * part of it lies within the given range.
1799 1800
 * Also note that if dissolve_free_huge_page() returns with an error, all
 * free hugepages that were dissolved before that error are lost.
1801
 */
1802
int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
1803 1804
{
	unsigned long pfn;
1805
	struct page *page;
1806
	int rc = 0;
1807

1808
	if (!hugepages_supported())
1809
		return rc;
1810

1811 1812
	for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
		page = pfn_to_page(pfn);
1813 1814 1815
		rc = dissolve_free_huge_page(page);
		if (rc)
			break;
1816
	}
1817 1818

	return rc;
1819 1820
}

1821 1822 1823
/*
 * Allocates a fresh surplus page from the page allocator.
 */
1824
static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
1825
		int nid, nodemask_t *nmask)
1826
{
1827
	struct page *page = NULL;
1828

1829
	if (hstate_is_gigantic(h))
1830 1831
		return NULL;

1832
	spin_lock(&hugetlb_lock);
1833 1834
	if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
		goto out_unlock;
1835 1836
	spin_unlock(&hugetlb_lock);

1837
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1838
	if (!page)
1839
		return NULL;
1840 1841

	spin_lock(&hugetlb_lock);
1842 1843 1844 1845 1846 1847 1848 1849 1850
	/*
	 * 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);
1851
		spin_unlock(&hugetlb_lock);
1852
		put_page(page);
1853
		return NULL;
1854 1855
	} else {
		h->surplus_huge_pages++;
1856
		h->surplus_huge_pages_node[page_to_nid(page)]++;
1857
	}
1858 1859

out_unlock:
1860
	spin_unlock(&hugetlb_lock);
1861 1862 1863 1864

	return page;
}

1865
static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
1866
				     int nid, nodemask_t *nmask)
1867 1868 1869 1870 1871 1872
{
	struct page *page;

	if (hstate_is_gigantic(h))
		return NULL;

1873
	page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885
	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;
}

1886 1887 1888
/*
 * Use the VMA's mpolicy to allocate a huge page from the buddy.
 */
D
Dave Hansen 已提交
1889
static
1890
struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
1891 1892
		struct vm_area_struct *vma, unsigned long addr)
{
1893 1894 1895 1896 1897 1898 1899
	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);
1900
	page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
1901 1902 1903
	mpol_cond_put(mpol);

	return page;
1904 1905
}

1906
/* page migration callback function */
1907
struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
1908
		nodemask_t *nmask, gfp_t gfp_mask)
1909 1910 1911
{
	spin_lock(&hugetlb_lock);
	if (h->free_huge_pages - h->resv_huge_pages > 0) {
1912 1913 1914 1915 1916 1917
		struct page *page;

		page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
		if (page) {
			spin_unlock(&hugetlb_lock);
			return page;
1918 1919 1920 1921
		}
	}
	spin_unlock(&hugetlb_lock);

1922
	return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
1923 1924
}

1925
/* mempolicy aware migration callback */
1926 1927
struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
		unsigned long address)
1928 1929 1930 1931 1932 1933 1934 1935 1936
{
	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);
1937
	page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
1938 1939 1940 1941 1942
	mpol_cond_put(mpol);

	return page;
}

1943
/*
L
Lucas De Marchi 已提交
1944
 * Increase the hugetlb pool such that it can accommodate a reservation
1945 1946
 * of size 'delta'.
 */
1947
static int gather_surplus_pages(struct hstate *h, int delta)
1948
	__must_hold(&hugetlb_lock)
1949 1950 1951 1952 1953
{
	struct list_head surplus_list;
	struct page *page, *tmp;
	int ret, i;
	int needed, allocated;
1954
	bool alloc_ok = true;
1955

1956
	needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
1957
	if (needed <= 0) {
1958
		h->resv_huge_pages += delta;
1959
		return 0;
1960
	}
1961 1962 1963 1964 1965 1966 1967 1968

	allocated = 0;
	INIT_LIST_HEAD(&surplus_list);

	ret = -ENOMEM;
retry:
	spin_unlock(&hugetlb_lock);
	for (i = 0; i < needed; i++) {
1969
		page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
1970
				NUMA_NO_NODE, NULL);
1971 1972 1973 1974
		if (!page) {
			alloc_ok = false;
			break;
		}
1975
		list_add(&page->lru, &surplus_list);
1976
		cond_resched();
1977
	}
1978
	allocated += i;
1979 1980 1981 1982 1983 1984

	/*
	 * 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);
1985 1986
	needed = (h->resv_huge_pages + delta) -
			(h->free_huge_pages + allocated);
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996
	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;
	}
1997 1998
	/*
	 * The surplus_list now contains _at_least_ the number of extra pages
L
Lucas De Marchi 已提交
1999
	 * needed to accommodate the reservation.  Add the appropriate number
2000
	 * of pages to the hugetlb pool and free the extras back to the buddy
2001 2002 2003
	 * 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.
2004 2005
	 */
	needed += allocated;
2006
	h->resv_huge_pages += delta;
2007
	ret = 0;
2008

2009
	/* Free the needed pages to the hugetlb pool */
2010
	list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
2011 2012
		if ((--needed) < 0)
			break;
2013 2014 2015 2016 2017
		/*
		 * This page is now managed by the hugetlb allocator and has
		 * no users -- drop the buddy allocator's reference.
		 */
		put_page_testzero(page);
2018
		VM_BUG_ON_PAGE(page_count(page), page);
2019
		enqueue_huge_page(h, page);
2020
	}
2021
free:
2022
	spin_unlock(&hugetlb_lock);
2023 2024

	/* Free unnecessary surplus pages to the buddy allocator */
2025 2026
	list_for_each_entry_safe(page, tmp, &surplus_list, lru)
		put_page(page);
2027
	spin_lock(&hugetlb_lock);
2028 2029 2030 2031 2032

	return ret;
}

/*
2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044
 * 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.
2045
 */
2046 2047
static void return_unused_surplus_pages(struct hstate *h,
					unsigned long unused_resv_pages)
2048 2049 2050
{
	unsigned long nr_pages;

2051
	/* Cannot return gigantic pages currently */
2052
	if (hstate_is_gigantic(h))
2053
		goto out;
2054

2055 2056 2057 2058
	/*
	 * Part (or even all) of the reservation could have been backed
	 * by pre-allocated pages. Only free surplus pages.
	 */
2059
	nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
2060

2061 2062
	/*
	 * We want to release as many surplus pages as possible, spread
2063 2064 2065
	 * 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.
2066
	 * free_pool_huge_page() will balance the freed pages across the
2067
	 * on-line nodes with memory and will handle the hstate accounting.
2068 2069 2070 2071
	 *
	 * 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.
2072 2073
	 */
	while (nr_pages--) {
2074 2075
		h->resv_huge_pages--;
		unused_resv_pages--;
2076
		if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
2077
			goto out;
2078
		cond_resched_lock(&hugetlb_lock);
2079
	}
2080 2081 2082 2083

out:
	/* Fully uncommit the reservation */
	h->resv_huge_pages -= unused_resv_pages;
2084 2085
}

2086

2087
/*
2088
 * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
2089
 * are used by the huge page allocation routines to manage reservations.
2090 2091 2092 2093 2094 2095
 *
 * 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
2096 2097 2098
 * 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.
2099 2100 2101 2102 2103 2104
 *
 * 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.
2105 2106 2107 2108 2109
 *
 * 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.
2110
 */
2111 2112 2113
enum vma_resv_mode {
	VMA_NEEDS_RESV,
	VMA_COMMIT_RESV,
2114
	VMA_END_RESV,
2115
	VMA_ADD_RESV,
2116
};
2117 2118
static long __vma_reservation_common(struct hstate *h,
				struct vm_area_struct *vma, unsigned long addr,
2119
				enum vma_resv_mode mode)
2120
{
2121 2122
	struct resv_map *resv;
	pgoff_t idx;
2123
	long ret;
2124
	long dummy_out_regions_needed;
2125

2126 2127
	resv = vma_resv_map(vma);
	if (!resv)
2128
		return 1;
2129

2130
	idx = vma_hugecache_offset(h, vma, addr);
2131 2132
	switch (mode) {
	case VMA_NEEDS_RESV:
2133 2134 2135 2136 2137 2138
		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);
2139 2140
		break;
	case VMA_COMMIT_RESV:
2141
		ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2142 2143
		/* region_add calls of range 1 should never fail. */
		VM_BUG_ON(ret < 0);
2144
		break;
2145
	case VMA_END_RESV:
2146
		region_abort(resv, idx, idx + 1, 1);
2147 2148
		ret = 0;
		break;
2149
	case VMA_ADD_RESV:
2150
		if (vma->vm_flags & VM_MAYSHARE) {
2151
			ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
2152 2153 2154 2155
			/* region_add calls of range 1 should never fail. */
			VM_BUG_ON(ret < 0);
		} else {
			region_abort(resv, idx, idx + 1, 1);
2156 2157 2158
			ret = region_del(resv, idx, idx + 1);
		}
		break;
2159 2160 2161
	default:
		BUG();
	}
2162

2163
	if (vma->vm_flags & VM_MAYSHARE)
2164
		return ret;
2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183
	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;
	}
2184
	else
2185
		return ret < 0 ? ret : 0;
2186
}
2187 2188

static long vma_needs_reservation(struct hstate *h,
2189
			struct vm_area_struct *vma, unsigned long addr)
2190
{
2191
	return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
2192
}
2193

2194 2195 2196
static long vma_commit_reservation(struct hstate *h,
			struct vm_area_struct *vma, unsigned long addr)
{
2197 2198 2199
	return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
}

2200
static void vma_end_reservation(struct hstate *h,
2201 2202
			struct vm_area_struct *vma, unsigned long addr)
{
2203
	(void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
2204 2205
}

2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255
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);
	}
}

2256
struct page *alloc_huge_page(struct vm_area_struct *vma,
2257
				    unsigned long addr, int avoid_reserve)
L
Linus Torvalds 已提交
2258
{
2259
	struct hugepage_subpool *spool = subpool_vma(vma);
2260
	struct hstate *h = hstate_vma(vma);
2261
	struct page *page;
2262 2263
	long map_chg, map_commit;
	long gbl_chg;
2264 2265
	int ret, idx;
	struct hugetlb_cgroup *h_cg;
2266
	bool deferred_reserve;
2267

2268
	idx = hstate_index(h);
2269
	/*
2270 2271 2272
	 * 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).
2273
	 */
2274 2275
	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
	if (map_chg < 0)
2276
		return ERR_PTR(-ENOMEM);
2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287

	/*
	 * 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) {
2288
			vma_end_reservation(h, vma, addr);
2289
			return ERR_PTR(-ENOSPC);
2290
		}
L
Linus Torvalds 已提交
2291

2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303
		/*
		 * 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;
	}

2304 2305 2306 2307 2308 2309 2310 2311 2312 2313
	/* 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;
	}

2314
	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
2315
	if (ret)
2316
		goto out_uncharge_cgroup_reservation;
2317

L
Linus Torvalds 已提交
2318
	spin_lock(&hugetlb_lock);
2319 2320 2321 2322 2323 2324
	/*
	 * 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);
2325
	if (!page) {
2326
		spin_unlock(&hugetlb_lock);
2327
		page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
2328 2329
		if (!page)
			goto out_uncharge_cgroup;
2330 2331 2332 2333
		if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
			SetPagePrivate(page);
			h->resv_huge_pages--;
		}
2334
		spin_lock(&hugetlb_lock);
2335
		list_add(&page->lru, &h->hugepage_activelist);
2336
		/* Fall through */
K
Ken Chen 已提交
2337
	}
2338
	hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
2339 2340 2341 2342 2343 2344 2345 2346
	/* 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);
	}

2347
	spin_unlock(&hugetlb_lock);
2348

2349
	set_page_private(page, (unsigned long)spool);
2350

2351 2352
	map_commit = vma_commit_reservation(h, vma, addr);
	if (unlikely(map_chg > map_commit)) {
2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365
		/*
		 * 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);
2366 2367 2368
		if (deferred_reserve)
			hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
					pages_per_huge_page(h), page);
2369
	}
2370
	return page;
2371 2372 2373

out_uncharge_cgroup:
	hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
2374 2375 2376 2377
out_uncharge_cgroup_reservation:
	if (deferred_reserve)
		hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
						    h_cg);
2378
out_subpool_put:
2379
	if (map_chg || avoid_reserve)
2380
		hugepage_subpool_put_pages(spool, 1);
2381
	vma_end_reservation(h, vma, addr);
2382
	return ERR_PTR(-ENOSPC);
2383 2384
}

2385 2386 2387
int alloc_bootmem_huge_page(struct hstate *h)
	__attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
int __alloc_bootmem_huge_page(struct hstate *h)
2388 2389
{
	struct huge_bootmem_page *m;
2390
	int nr_nodes, node;
2391

2392
	for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
2393 2394
		void *addr;

2395
		addr = memblock_alloc_try_nid_raw(
2396
				huge_page_size(h), huge_page_size(h),
2397
				0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
2398 2399 2400 2401 2402 2403 2404
		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;
2405
			goto found;
2406 2407 2408 2409 2410
		}
	}
	return 0;

found:
2411
	BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
2412
	/* Put them into a private list first because mem_map is not up yet */
2413
	INIT_LIST_HEAD(&m->list);
2414 2415 2416 2417 2418
	list_add(&m->list, &huge_boot_pages);
	m->hstate = h;
	return 1;
}

2419 2420
static void __init prep_compound_huge_page(struct page *page,
		unsigned int order)
2421 2422 2423 2424 2425 2426 2427
{
	if (unlikely(order > (MAX_ORDER - 1)))
		prep_compound_gigantic_page(page, order);
	else
		prep_compound_page(page, order);
}

2428 2429 2430 2431 2432 2433
/* 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) {
2434
		struct page *page = virt_to_page(m);
2435
		struct hstate *h = m->hstate;
2436

2437
		WARN_ON(page_count(page) != 1);
2438
		prep_compound_huge_page(page, h->order);
2439
		WARN_ON(PageReserved(page));
2440
		prep_new_huge_page(h, page, page_to_nid(page));
2441 2442
		put_page(page); /* free it into the hugepage allocator */

2443 2444 2445 2446 2447 2448
		/*
		 * 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.
		 */
2449
		if (hstate_is_gigantic(h))
2450
			adjust_managed_page_count(page, 1 << h->order);
2451
		cond_resched();
2452 2453 2454
	}
}

2455
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
L
Linus Torvalds 已提交
2456 2457
{
	unsigned long i;
2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476
	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);
2477

2478
	for (i = 0; i < h->max_huge_pages; ++i) {
2479
		if (hstate_is_gigantic(h)) {
2480
			if (hugetlb_cma_size) {
2481 2482 2483
				pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
				break;
			}
2484 2485
			if (!alloc_bootmem_huge_page(h))
				break;
2486
		} else if (!alloc_pool_huge_page(h,
2487 2488
					 &node_states[N_MEMORY],
					 node_alloc_noretry))
L
Linus Torvalds 已提交
2489
			break;
2490
		cond_resched();
L
Linus Torvalds 已提交
2491
	}
2492 2493 2494
	if (i < h->max_huge_pages) {
		char buf[32];

2495
		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2496 2497 2498 2499
		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;
	}
2500 2501

	kfree(node_alloc_noretry);
2502 2503 2504 2505 2506 2507 2508
}

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

	for_each_hstate(h) {
2509 2510 2511
		if (minimum_order > huge_page_order(h))
			minimum_order = huge_page_order(h);

2512
		/* oversize hugepages were init'ed in early boot */
2513
		if (!hstate_is_gigantic(h))
2514
			hugetlb_hstate_alloc_pages(h);
2515
	}
2516
	VM_BUG_ON(minimum_order == UINT_MAX);
2517 2518 2519 2520 2521 2522 2523
}

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

	for_each_hstate(h) {
A
Andi Kleen 已提交
2524
		char buf[32];
2525 2526

		string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
2527
		pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
2528
			buf, h->free_huge_pages);
2529 2530 2531
	}
}

L
Linus Torvalds 已提交
2532
#ifdef CONFIG_HIGHMEM
2533 2534
static void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2535
{
2536 2537
	int i;

2538
	if (hstate_is_gigantic(h))
2539 2540
		return;

2541
	for_each_node_mask(i, *nodes_allowed) {
L
Linus Torvalds 已提交
2542
		struct page *page, *next;
2543 2544 2545
		struct list_head *freel = &h->hugepage_freelists[i];
		list_for_each_entry_safe(page, next, freel, lru) {
			if (count >= h->nr_huge_pages)
2546
				return;
L
Linus Torvalds 已提交
2547 2548 2549
			if (PageHighMem(page))
				continue;
			list_del(&page->lru);
2550
			update_and_free_page(h, page);
2551 2552
			h->free_huge_pages--;
			h->free_huge_pages_node[page_to_nid(page)]--;
L
Linus Torvalds 已提交
2553 2554 2555 2556
		}
	}
}
#else
2557 2558
static inline void try_to_free_low(struct hstate *h, unsigned long count,
						nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2559 2560 2561 2562
{
}
#endif

2563 2564 2565 2566 2567
/*
 * 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.
 */
2568 2569
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
				int delta)
2570
{
2571
	int nr_nodes, node;
2572 2573 2574

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

2575 2576 2577 2578
	if (delta < 0) {
		for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
			if (h->surplus_huge_pages_node[node])
				goto found;
2579
		}
2580 2581 2582 2583 2584
	} 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;
2585
		}
2586 2587
	}
	return 0;
2588

2589 2590 2591 2592
found:
	h->surplus_huge_pages += delta;
	h->surplus_huge_pages_node[node] += delta;
	return 1;
2593 2594
}

2595
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
2596
static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
2597
			      nodemask_t *nodes_allowed)
L
Linus Torvalds 已提交
2598
{
2599
	unsigned long min_count, ret;
2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610
	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
2611

2612 2613
	spin_lock(&hugetlb_lock);

2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633
	/*
	 * 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;
	}

2634 2635 2636 2637 2638 2639 2640 2641 2642 2643
	/*
	 * 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);
2644
			NODEMASK_FREE(node_alloc_noretry);
2645 2646 2647 2648
			return -EINVAL;
		}
		/* Fall through to decrease pool */
	}
2649

2650 2651 2652 2653
	/*
	 * Increase the pool size
	 * First take pages out of surplus state.  Then make up the
	 * remaining difference by allocating fresh huge pages.
2654
	 *
2655
	 * We might race with alloc_surplus_huge_page() here and be unable
2656 2657 2658 2659
	 * 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.
2660
	 */
2661
	while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
2662
		if (!adjust_pool_surplus(h, nodes_allowed, -1))
2663 2664 2665
			break;
	}

2666
	while (count > persistent_huge_pages(h)) {
2667 2668 2669 2670 2671 2672
		/*
		 * 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);
2673 2674 2675 2676

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

2677 2678
		ret = alloc_pool_huge_page(h, nodes_allowed,
						node_alloc_noretry);
2679 2680 2681 2682
		spin_lock(&hugetlb_lock);
		if (!ret)
			goto out;

2683 2684 2685
		/* Bail for signals. Probably ctrl-c from user */
		if (signal_pending(current))
			goto out;
2686 2687 2688 2689 2690 2691 2692 2693
	}

	/*
	 * 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.
2694 2695 2696 2697
	 *
	 * 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
2698
	 * alloc_surplus_huge_page() is checking the global counter,
2699 2700 2701
	 * 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.
2702
	 */
2703
	min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
2704
	min_count = max(count, min_count);
2705
	try_to_free_low(h, min_count, nodes_allowed);
2706
	while (min_count < persistent_huge_pages(h)) {
2707
		if (!free_pool_huge_page(h, nodes_allowed, 0))
L
Linus Torvalds 已提交
2708
			break;
2709
		cond_resched_lock(&hugetlb_lock);
L
Linus Torvalds 已提交
2710
	}
2711
	while (count < persistent_huge_pages(h)) {
2712
		if (!adjust_pool_surplus(h, nodes_allowed, 1))
2713 2714 2715
			break;
	}
out:
2716
	h->max_huge_pages = persistent_huge_pages(h);
L
Linus Torvalds 已提交
2717
	spin_unlock(&hugetlb_lock);
2718

2719 2720
	NODEMASK_FREE(node_alloc_noretry);

2721
	return 0;
L
Linus Torvalds 已提交
2722 2723
}

2724 2725 2726 2727 2728 2729 2730 2731 2732 2733
#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];

2734 2735 2736
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);

static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
2737 2738
{
	int i;
2739

2740
	for (i = 0; i < HUGE_MAX_HSTATE; i++)
2741 2742 2743
		if (hstate_kobjs[i] == kobj) {
			if (nidp)
				*nidp = NUMA_NO_NODE;
2744
			return &hstates[i];
2745 2746 2747
		}

	return kobj_to_node_hstate(kobj, nidp);
2748 2749
}

2750
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
2751 2752
					struct kobj_attribute *attr, char *buf)
{
2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763
	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);
2764
}
2765

2766 2767 2768
static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
					   struct hstate *h, int nid,
					   unsigned long count, size_t len)
2769 2770
{
	int err;
2771
	nodemask_t nodes_allowed, *n_mask;
2772

2773 2774
	if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
		return -EINVAL;
2775

2776 2777 2778 2779 2780
	if (nid == NUMA_NO_NODE) {
		/*
		 * global hstate attribute
		 */
		if (!(obey_mempolicy &&
2781 2782 2783 2784 2785
				init_nodemask_of_mempolicy(&nodes_allowed)))
			n_mask = &node_states[N_MEMORY];
		else
			n_mask = &nodes_allowed;
	} else {
2786
		/*
2787 2788
		 * Node specific request.  count adjustment happens in
		 * set_max_huge_pages() after acquiring hugetlb_lock.
2789
		 */
2790 2791
		init_nodemask_of_node(&nodes_allowed, nid);
		n_mask = &nodes_allowed;
2792
	}
2793

2794
	err = set_max_huge_pages(h, count, nid, n_mask);
2795

2796
	return err ? err : len;
2797 2798
}

2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815
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);
}

2816 2817 2818 2819 2820 2821 2822 2823 2824
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)
{
2825
	return nr_hugepages_store_common(false, kobj, buf, len);
2826 2827 2828
}
HSTATE_ATTR(nr_hugepages);

2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843
#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)
{
2844
	return nr_hugepages_store_common(true, kobj, buf, len);
2845 2846 2847 2848 2849
}
HSTATE_ATTR(nr_hugepages_mempolicy);
#endif


2850 2851 2852
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2853
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2854 2855
	return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
}
2856

2857 2858 2859 2860 2861
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;
2862
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2863

2864
	if (hstate_is_gigantic(h))
2865 2866
		return -EINVAL;

2867
	err = kstrtoul(buf, 10, &input);
2868
	if (err)
2869
		return err;
2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881

	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)
{
2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892
	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);
2893 2894 2895 2896 2897 2898
}
HSTATE_ATTR_RO(free_hugepages);

static ssize_t resv_hugepages_show(struct kobject *kobj,
					struct kobj_attribute *attr, char *buf)
{
2899
	struct hstate *h = kobj_to_hstate(kobj, NULL);
2900 2901 2902 2903 2904 2905 2906
	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)
{
2907 2908 2909 2910 2911 2912 2913 2914 2915 2916 2917
	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);
2918 2919 2920 2921 2922 2923 2924 2925 2926
}
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,
2927 2928 2929
#ifdef CONFIG_NUMA
	&nr_hugepages_mempolicy_attr.attr,
#endif
2930 2931 2932
	NULL,
};

2933
static const struct attribute_group hstate_attr_group = {
2934 2935 2936
	.attrs = hstate_attrs,
};

J
Jeff Mahoney 已提交
2937 2938
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
				    struct kobject **hstate_kobjs,
2939
				    const struct attribute_group *hstate_attr_group)
2940 2941
{
	int retval;
2942
	int hi = hstate_index(h);
2943

2944 2945
	hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
	if (!hstate_kobjs[hi])
2946 2947
		return -ENOMEM;

2948
	retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
2949
	if (retval)
2950
		kobject_put(hstate_kobjs[hi]);
2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964

	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) {
2965 2966
		err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
					 hstate_kobjs, &hstate_attr_group);
2967
		if (err)
2968
			pr_err("HugeTLB: Unable to add hstate %s", h->name);
2969 2970 2971
	}
}

2972 2973 2974 2975
#ifdef CONFIG_NUMA

/*
 * node_hstate/s - associate per node hstate attributes, via their kobjects,
2976 2977 2978
 * 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
2979 2980 2981 2982 2983 2984
 * the base kernel, on the hugetlb module.
 */
struct node_hstate {
	struct kobject		*hugepages_kobj;
	struct kobject		*hstate_kobjs[HUGE_MAX_HSTATE];
};
2985
static struct node_hstate node_hstates[MAX_NUMNODES];
2986 2987

/*
2988
 * A subset of global hstate attributes for node devices
2989 2990 2991 2992 2993 2994 2995 2996
 */
static struct attribute *per_node_hstate_attrs[] = {
	&nr_hugepages_attr.attr,
	&free_hugepages_attr.attr,
	&surplus_hugepages_attr.attr,
	NULL,
};

2997
static const struct attribute_group per_node_hstate_attr_group = {
2998 2999 3000 3001
	.attrs = per_node_hstate_attrs,
};

/*
3002
 * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024
 * 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;
}

/*
3025
 * Unregister hstate attributes from a single node device.
3026 3027
 * No-op if no hstate attributes attached.
 */
3028
static void hugetlb_unregister_node(struct node *node)
3029 3030
{
	struct hstate *h;
3031
	struct node_hstate *nhs = &node_hstates[node->dev.id];
3032 3033

	if (!nhs->hugepages_kobj)
3034
		return;		/* no hstate attributes */
3035

3036 3037 3038 3039 3040
	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;
3041
		}
3042
	}
3043 3044 3045 3046 3047 3048 3049

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


/*
3050
 * Register hstate attributes for a single node device.
3051 3052
 * No-op if attributes already registered.
 */
3053
static void hugetlb_register_node(struct node *node)
3054 3055
{
	struct hstate *h;
3056
	struct node_hstate *nhs = &node_hstates[node->dev.id];
3057 3058 3059 3060 3061 3062
	int err;

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

	nhs->hugepages_kobj = kobject_create_and_add("hugepages",
3063
							&node->dev.kobj);
3064 3065 3066 3067 3068 3069 3070 3071
	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) {
3072
			pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
3073
				h->name, node->dev.id);
3074 3075 3076 3077 3078 3079 3080
			hugetlb_unregister_node(node);
			break;
		}
	}
}

/*
3081
 * hugetlb init time:  register hstate attributes for all registered node
3082 3083
 * devices of nodes that have memory.  All on-line nodes should have
 * registered their associated device by this time.
3084
 */
3085
static void __init hugetlb_register_all_nodes(void)
3086 3087 3088
{
	int nid;

3089
	for_each_node_state(nid, N_MEMORY) {
3090
		struct node *node = node_devices[nid];
3091
		if (node->dev.id == nid)
3092 3093 3094 3095
			hugetlb_register_node(node);
	}

	/*
3096
	 * Let the node device driver know we're here so it can
3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115
	 * [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

3116 3117
static int __init hugetlb_init(void)
{
3118 3119
	int i;

3120 3121 3122
	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");
3123
		return 0;
3124
	}
3125

3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153
	/*
	 * 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;
3154
		}
3155
	}
3156

3157
	hugetlb_cma_check();
3158
	hugetlb_init_hstates();
3159
	gather_bootmem_prealloc();
3160 3161 3162
	report_hugepages();

	hugetlb_sysfs_init();
3163
	hugetlb_register_all_nodes();
3164
	hugetlb_cgroup_file_init();
3165

3166 3167 3168 3169 3170
#ifdef CONFIG_SMP
	num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
#else
	num_fault_mutexes = 1;
#endif
3171
	hugetlb_fault_mutex_table =
3172 3173
		kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
			      GFP_KERNEL);
3174
	BUG_ON(!hugetlb_fault_mutex_table);
3175 3176

	for (i = 0; i < num_fault_mutexes; i++)
3177
		mutex_init(&hugetlb_fault_mutex_table[i]);
3178 3179
	return 0;
}
3180
subsys_initcall(hugetlb_init);
3181

3182 3183
/* Overwritten by architectures with more huge page sizes */
bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
3184
{
3185
	return size == HPAGE_SIZE;
3186 3187
}

3188
void __init hugetlb_add_hstate(unsigned int order)
3189 3190
{
	struct hstate *h;
3191 3192
	unsigned long i;

3193 3194 3195
	if (size_to_hstate(PAGE_SIZE << order)) {
		return;
	}
3196
	BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
3197
	BUG_ON(order == 0);
3198
	h = &hstates[hugetlb_max_hstate++];
3199 3200
	h->order = order;
	h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
3201 3202 3203 3204
	h->nr_huge_pages = 0;
	h->free_huge_pages = 0;
	for (i = 0; i < MAX_NUMNODES; ++i)
		INIT_LIST_HEAD(&h->hugepage_freelists[i]);
3205
	INIT_LIST_HEAD(&h->hugepage_activelist);
3206 3207
	h->next_nid_to_alloc = first_memory_node;
	h->next_nid_to_free = first_memory_node;
3208 3209
	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
					huge_page_size(h)/1024);
3210

3211 3212 3213
	parsed_hstate = h;
}

3214 3215 3216 3217 3218 3219 3220 3221
/*
 * 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)
3222 3223
{
	unsigned long *mhp;
3224
	static unsigned long *last_mhp;
3225

3226
	if (!parsed_valid_hugepagesz) {
3227
		pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
3228
		parsed_valid_hugepagesz = true;
3229
		return 0;
3230
	}
3231

3232
	/*
3233 3234 3235 3236
	 * !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.
3237
	 */
3238
	else if (!hugetlb_max_hstate)
3239 3240 3241 3242
		mhp = &default_hstate_max_huge_pages;
	else
		mhp = &parsed_hstate->max_huge_pages;

3243
	if (mhp == last_mhp) {
3244 3245
		pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
		return 0;
3246 3247
	}

3248 3249 3250
	if (sscanf(s, "%lu", mhp) <= 0)
		*mhp = 0;

3251 3252 3253 3254 3255
	/*
	 * 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.
	 */
3256
	if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
3257 3258 3259 3260
		hugetlb_hstate_alloc_pages(parsed_hstate);

	last_mhp = mhp;

3261 3262
	return 1;
}
3263
__setup("hugepages=", hugepages_setup);
3264

3265 3266 3267 3268 3269 3270 3271
/*
 * 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.
 */
3272
static int __init hugepagesz_setup(char *s)
3273
{
3274
	unsigned long size;
3275 3276 3277
	struct hstate *h;

	parsed_valid_hugepagesz = false;
3278 3279 3280
	size = (unsigned long)memparse(s, NULL);

	if (!arch_hugetlb_valid_size(size)) {
3281
		pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
3282 3283 3284
		return 0;
	}

3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307
	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;
3308 3309
	}

3310
	hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
3311
	parsed_valid_hugepagesz = true;
3312 3313
	return 1;
}
3314 3315
__setup("hugepagesz=", hugepagesz_setup);

3316 3317 3318 3319
/*
 * default_hugepagesz command line input
 * Only one instance of default_hugepagesz allowed on command line.
 */
3320
static int __init default_hugepagesz_setup(char *s)
3321
{
3322 3323
	unsigned long size;

3324 3325 3326 3327 3328 3329
	parsed_valid_hugepagesz = false;
	if (parsed_default_hugepagesz) {
		pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
		return 0;
	}

3330 3331 3332
	size = (unsigned long)memparse(s, NULL);

	if (!arch_hugetlb_valid_size(size)) {
3333
		pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
3334 3335 3336
		return 0;
	}

3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355
	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;
	}

3356 3357
	return 1;
}
3358
__setup("default_hugepagesz=", default_hugepagesz_setup);
3359

3360
static unsigned int allowed_mems_nr(struct hstate *h)
3361 3362 3363
{
	int node;
	unsigned int nr = 0;
3364 3365 3366 3367 3368
	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);
3369

3370 3371 3372 3373 3374
	for_each_node_mask(node, cpuset_current_mems_allowed) {
		if (!mpol_allowed ||
		    (mpol_allowed && node_isset(node, *mpol_allowed)))
			nr += array[node];
	}
3375 3376 3377 3378 3379

	return nr;
}

#ifdef CONFIG_SYSCTL
3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395
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);
}

3396 3397
static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
			 struct ctl_table *table, int write,
3398
			 void *buffer, size_t *length, loff_t *ppos)
L
Linus Torvalds 已提交
3399
{
3400
	struct hstate *h = &default_hstate;
3401
	unsigned long tmp = h->max_huge_pages;
3402
	int ret;
3403

3404
	if (!hugepages_supported())
3405
		return -EOPNOTSUPP;
3406

3407 3408
	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
					     &tmp);
3409 3410
	if (ret)
		goto out;
3411

3412 3413 3414
	if (write)
		ret = __nr_hugepages_store_common(obey_mempolicy, h,
						  NUMA_NO_NODE, tmp, *length);
3415 3416
out:
	return ret;
L
Linus Torvalds 已提交
3417
}
3418

3419
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
3420
			  void *buffer, size_t *length, loff_t *ppos)
3421 3422 3423 3424 3425 3426 3427 3428
{

	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,
3429
			  void *buffer, size_t *length, loff_t *ppos)
3430 3431 3432 3433 3434 3435
{
	return hugetlb_sysctl_handler_common(true, table, write,
							buffer, length, ppos);
}
#endif /* CONFIG_NUMA */

3436
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
3437
		void *buffer, size_t *length, loff_t *ppos)
3438
{
3439
	struct hstate *h = &default_hstate;
3440
	unsigned long tmp;
3441
	int ret;
3442

3443
	if (!hugepages_supported())
3444
		return -EOPNOTSUPP;
3445

3446
	tmp = h->nr_overcommit_huge_pages;
3447

3448
	if (write && hstate_is_gigantic(h))
3449 3450
		return -EINVAL;

3451 3452
	ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
					     &tmp);
3453 3454
	if (ret)
		goto out;
3455 3456 3457 3458 3459 3460

	if (write) {
		spin_lock(&hugetlb_lock);
		h->nr_overcommit_huge_pages = tmp;
		spin_unlock(&hugetlb_lock);
	}
3461 3462
out:
	return ret;
3463 3464
}

L
Linus Torvalds 已提交
3465 3466
#endif /* CONFIG_SYSCTL */

3467
void hugetlb_report_meminfo(struct seq_file *m)
L
Linus Torvalds 已提交
3468
{
3469 3470 3471
	struct hstate *h;
	unsigned long total = 0;

3472 3473
	if (!hugepages_supported())
		return;
3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494

	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
3495 3496
}

3497
int hugetlb_report_node_meminfo(char *buf, int len, int nid)
L
Linus Torvalds 已提交
3498
{
3499
	struct hstate *h = &default_hstate;
3500

3501 3502
	if (!hugepages_supported())
		return 0;
3503 3504 3505 3506 3507 3508 3509 3510

	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
3511 3512
}

3513 3514 3515 3516 3517
void hugetlb_show_meminfo(void)
{
	struct hstate *h;
	int nid;

3518 3519 3520
	if (!hugepages_supported())
		return;

3521 3522 3523 3524 3525 3526 3527 3528 3529 3530
	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));
}

3531 3532 3533 3534 3535 3536
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
3537 3538 3539
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
unsigned long hugetlb_total_pages(void)
{
3540 3541 3542 3543 3544 3545
	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
3546 3547
}

3548
static int hugetlb_acct_memory(struct hstate *h, long delta)
M
Mel Gorman 已提交
3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568
{
	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.
3569 3570 3571 3572 3573 3574
	 *
	 * 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
3575 3576
	 */
	if (delta > 0) {
3577
		if (gather_surplus_pages(h, delta) < 0)
M
Mel Gorman 已提交
3578 3579
			goto out;

3580
		if (delta > allowed_mems_nr(h)) {
3581
			return_unused_surplus_pages(h, delta);
M
Mel Gorman 已提交
3582 3583 3584 3585 3586 3587
			goto out;
		}
	}

	ret = 0;
	if (delta < 0)
3588
		return_unused_surplus_pages(h, (unsigned long) -delta);
M
Mel Gorman 已提交
3589 3590 3591 3592 3593 3594

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

3595 3596
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
{
3597
	struct resv_map *resv = vma_resv_map(vma);
3598 3599 3600 3601 3602

	/*
	 * 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
3603
	 * has a reference to the reservation map it cannot disappear until
3604 3605 3606
	 * after this open call completes.  It is therefore safe to take a
	 * new reference here without additional locking.
	 */
3607
	if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
3608
		kref_get(&resv->refs);
3609 3610
}

3611 3612
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
{
3613
	struct hstate *h = hstate_vma(vma);
3614
	struct resv_map *resv = vma_resv_map(vma);
3615
	struct hugepage_subpool *spool = subpool_vma(vma);
3616
	unsigned long reserve, start, end;
3617
	long gbl_reserve;
3618

3619 3620
	if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		return;
3621

3622 3623
	start = vma_hugecache_offset(h, vma, vma->vm_start);
	end = vma_hugecache_offset(h, vma, vma->vm_end);
3624

3625
	reserve = (end - start) - region_count(resv, start, end);
3626
	hugetlb_cgroup_uncharge_counter(resv, start, end);
3627
	if (reserve) {
3628 3629 3630 3631 3632 3633
		/*
		 * 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);
3634
	}
3635 3636

	kref_put(&resv->refs, resv_map_release);
3637 3638
}

3639 3640 3641 3642 3643 3644 3645
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;
}

3646 3647 3648 3649 3650 3651 3652
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
3653 3654 3655 3656 3657 3658
/*
 * 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.
 */
3659
static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
L
Linus Torvalds 已提交
3660 3661
{
	BUG();
N
Nick Piggin 已提交
3662
	return 0;
L
Linus Torvalds 已提交
3663 3664
}

3665 3666 3667 3668 3669 3670 3671
/*
 * 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.
 */
3672
const struct vm_operations_struct hugetlb_vm_ops = {
N
Nick Piggin 已提交
3673
	.fault = hugetlb_vm_op_fault,
3674
	.open = hugetlb_vm_op_open,
3675
	.close = hugetlb_vm_op_close,
3676
	.split = hugetlb_vm_op_split,
3677
	.pagesize = hugetlb_vm_op_pagesize,
L
Linus Torvalds 已提交
3678 3679
};

3680 3681
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
				int writable)
D
David Gibson 已提交
3682 3683 3684
{
	pte_t entry;

3685
	if (writable) {
3686 3687
		entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
					 vma->vm_page_prot)));
D
David Gibson 已提交
3688
	} else {
3689 3690
		entry = huge_pte_wrprotect(mk_huge_pte(page,
					   vma->vm_page_prot));
D
David Gibson 已提交
3691 3692 3693
	}
	entry = pte_mkyoung(entry);
	entry = pte_mkhuge(entry);
3694
	entry = arch_make_huge_pte(entry, vma, page, writable);
D
David Gibson 已提交
3695 3696 3697 3698

	return entry;
}

3699 3700 3701 3702 3703
static void set_huge_ptep_writable(struct vm_area_struct *vma,
				   unsigned long address, pte_t *ptep)
{
	pte_t entry;

3704
	entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
3705
	if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
3706
		update_mmu_cache(vma, address, ptep);
3707 3708
}

3709
bool is_hugetlb_entry_migration(pte_t pte)
3710 3711 3712 3713
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3714
		return false;
3715
	swp = pte_to_swp_entry(pte);
3716
	if (is_migration_entry(swp))
3717
		return true;
3718
	else
3719
		return false;
3720 3721
}

3722
static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
3723 3724 3725 3726
{
	swp_entry_t swp;

	if (huge_pte_none(pte) || pte_present(pte))
3727
		return false;
3728
	swp = pte_to_swp_entry(pte);
3729
	if (is_hwpoison_entry(swp))
3730
		return true;
3731
	else
3732
		return false;
3733
}
3734

D
David Gibson 已提交
3735 3736 3737
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
			    struct vm_area_struct *vma)
{
3738
	pte_t *src_pte, *dst_pte, entry, dst_entry;
D
David Gibson 已提交
3739
	struct page *ptepage;
3740
	unsigned long addr;
3741
	int cow;
3742 3743
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3744
	struct address_space *mapping = vma->vm_file->f_mapping;
3745
	struct mmu_notifier_range range;
3746
	int ret = 0;
3747 3748

	cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
D
David Gibson 已提交
3749

3750
	if (cow) {
3751
		mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
3752
					vma->vm_start,
3753 3754
					vma->vm_end);
		mmu_notifier_invalidate_range_start(&range);
3755 3756 3757 3758 3759 3760 3761 3762
	} 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);
3763
	}
3764

3765
	for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
3766
		spinlock_t *src_ptl, *dst_ptl;
3767
		src_pte = huge_pte_offset(src, addr, sz);
H
Hugh Dickins 已提交
3768 3769
		if (!src_pte)
			continue;
3770
		dst_pte = huge_pte_alloc(dst, addr, sz);
3771 3772 3773 3774
		if (!dst_pte) {
			ret = -ENOMEM;
			break;
		}
3775

3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786
		/*
		 * 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))
3787 3788
			continue;

3789 3790 3791
		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);
3792
		entry = huge_ptep_get(src_pte);
3793 3794 3795 3796 3797 3798 3799
		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.
			 */
3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811
			;
		} 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);
3812 3813
				set_huge_swap_pte_at(src, addr, src_pte,
						     entry, sz);
3814
			}
3815
			set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
3816
		} else {
3817
			if (cow) {
3818 3819 3820 3821 3822
				/*
				 * No need to notify as we are downgrading page
				 * table protection not changing it to point
				 * to a new page.
				 *
3823
				 * See Documentation/vm/mmu_notifier.rst
3824
				 */
3825
				huge_ptep_set_wrprotect(src, addr, src_pte);
3826
			}
3827
			entry = huge_ptep_get(src_pte);
3828 3829
			ptepage = pte_page(entry);
			get_page(ptepage);
3830
			page_dup_rmap(ptepage, true);
3831
			set_huge_pte_at(dst, addr, dst_pte, entry);
3832
			hugetlb_count_add(pages_per_huge_page(h), dst);
3833
		}
3834 3835
		spin_unlock(src_ptl);
		spin_unlock(dst_ptl);
D
David Gibson 已提交
3836 3837
	}

3838
	if (cow)
3839
		mmu_notifier_invalidate_range_end(&range);
3840 3841
	else
		i_mmap_unlock_read(mapping);
3842 3843

	return ret;
D
David Gibson 已提交
3844 3845
}

3846 3847 3848
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
3849 3850 3851
{
	struct mm_struct *mm = vma->vm_mm;
	unsigned long address;
3852
	pte_t *ptep;
D
David Gibson 已提交
3853
	pte_t pte;
3854
	spinlock_t *ptl;
D
David Gibson 已提交
3855
	struct page *page;
3856 3857
	struct hstate *h = hstate_vma(vma);
	unsigned long sz = huge_page_size(h);
3858
	struct mmu_notifier_range range;
3859

D
David Gibson 已提交
3860
	WARN_ON(!is_vm_hugetlb_page(vma));
3861 3862
	BUG_ON(start & ~huge_page_mask(h));
	BUG_ON(end & ~huge_page_mask(h));
D
David Gibson 已提交
3863

3864 3865 3866 3867
	/*
	 * This is a hugetlb vma, all the pte entries should point
	 * to huge page.
	 */
3868
	tlb_change_page_size(tlb, sz);
3869
	tlb_start_vma(tlb, vma);
3870 3871 3872 3873

	/*
	 * If sharing possible, alert mmu notifiers of worst case.
	 */
3874 3875
	mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
				end);
3876 3877
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
	mmu_notifier_invalidate_range_start(&range);
3878 3879
	address = start;
	for (; address < end; address += sz) {
3880
		ptep = huge_pte_offset(mm, address, sz);
A
Adam Litke 已提交
3881
		if (!ptep)
3882 3883
			continue;

3884
		ptl = huge_pte_lock(h, mm, ptep);
3885
		if (huge_pmd_unshare(mm, vma, &address, ptep)) {
3886
			spin_unlock(ptl);
3887 3888 3889 3890
			/*
			 * We just unmapped a page of PMDs by clearing a PUD.
			 * The caller's TLB flush range should cover this area.
			 */
3891 3892
			continue;
		}
3893

3894
		pte = huge_ptep_get(ptep);
3895 3896 3897 3898
		if (huge_pte_none(pte)) {
			spin_unlock(ptl);
			continue;
		}
3899 3900

		/*
3901 3902
		 * Migrating hugepage or HWPoisoned hugepage is already
		 * unmapped and its refcount is dropped, so just clear pte here.
3903
		 */
3904
		if (unlikely(!pte_present(pte))) {
3905
			huge_pte_clear(mm, address, ptep, sz);
3906 3907
			spin_unlock(ptl);
			continue;
3908
		}
3909 3910

		page = pte_page(pte);
3911 3912 3913 3914 3915 3916
		/*
		 * 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) {
3917 3918 3919 3920
			if (page != ref_page) {
				spin_unlock(ptl);
				continue;
			}
3921 3922 3923 3924 3925 3926 3927 3928
			/*
			 * 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);
		}

3929
		pte = huge_ptep_get_and_clear(mm, address, ptep);
3930
		tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
3931
		if (huge_pte_dirty(pte))
3932
			set_page_dirty(page);
3933

3934
		hugetlb_count_sub(pages_per_huge_page(h), mm);
3935
		page_remove_rmap(page, true);
3936

3937
		spin_unlock(ptl);
3938
		tlb_remove_page_size(tlb, page, huge_page_size(h));
3939 3940 3941 3942 3943
		/*
		 * Bail out after unmapping reference page if supplied
		 */
		if (ref_page)
			break;
3944
	}
3945
	mmu_notifier_invalidate_range_end(&range);
3946
	tlb_end_vma(tlb, vma);
L
Linus Torvalds 已提交
3947
}
D
David Gibson 已提交
3948

3949 3950 3951 3952 3953 3954 3955 3956 3957 3958 3959 3960
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
3961
	 * is to clear it before releasing the i_mmap_rwsem. This works
3962
	 * because in the context this is called, the VMA is about to be
3963
	 * destroyed and the i_mmap_rwsem is held.
3964 3965 3966 3967
	 */
	vma->vm_flags &= ~VM_MAYSHARE;
}

3968
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
3969
			  unsigned long end, struct page *ref_page)
3970
{
3971 3972
	struct mm_struct *mm;
	struct mmu_gather tlb;
3973 3974 3975 3976 3977 3978 3979 3980 3981 3982 3983
	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);
3984 3985 3986

	mm = vma->vm_mm;

3987
	tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end);
3988
	__unmap_hugepage_range(&tlb, vma, start, end, ref_page);
3989
	tlb_finish_mmu(&tlb, tlb_start, tlb_end);
3990 3991
}

3992 3993 3994 3995 3996 3997
/*
 * 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.
 */
3998 3999
static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
			      struct page *page, unsigned long address)
4000
{
4001
	struct hstate *h = hstate_vma(vma);
4002 4003 4004 4005 4006 4007 4008 4009
	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.
	 */
4010
	address = address & huge_page_mask(h);
4011 4012
	pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
			vma->vm_pgoff;
4013
	mapping = vma->vm_file->f_mapping;
4014

4015 4016 4017 4018 4019
	/*
	 * 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
	 */
4020
	i_mmap_lock_write(mapping);
4021
	vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
4022 4023 4024 4025
		/* Do not unmap the current VMA */
		if (iter_vma == vma)
			continue;

4026 4027 4028 4029 4030 4031 4032 4033
		/*
		 * 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;

4034 4035 4036 4037 4038 4039 4040 4041
		/*
		 * 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))
4042 4043
			unmap_hugepage_range(iter_vma, address,
					     address + huge_page_size(h), page);
4044
	}
4045
	i_mmap_unlock_write(mapping);
4046 4047
}

4048 4049
/*
 * Hugetlb_cow() should be called with page lock of the original hugepage held.
4050 4051 4052
 * 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.
4053
 */
4054
static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
4055
		       unsigned long address, pte_t *ptep,
4056
		       struct page *pagecache_page, spinlock_t *ptl)
4057
{
4058
	pte_t pte;
4059
	struct hstate *h = hstate_vma(vma);
4060
	struct page *old_page, *new_page;
4061 4062
	int outside_reserve = 0;
	vm_fault_t ret = 0;
4063
	unsigned long haddr = address & huge_page_mask(h);
4064
	struct mmu_notifier_range range;
4065

4066
	pte = huge_ptep_get(ptep);
4067 4068
	old_page = pte_page(pte);

4069
retry_avoidcopy:
4070 4071
	/* If no-one else is actually using this page, avoid the copy
	 * and just make the page writable */
4072
	if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
4073
		page_move_anon_rmap(old_page, vma);
4074
		set_huge_ptep_writable(vma, haddr, ptep);
N
Nick Piggin 已提交
4075
		return 0;
4076 4077
	}

4078 4079 4080 4081 4082 4083 4084 4085 4086
	/*
	 * 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.
	 */
4087
	if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
4088 4089 4090
			old_page != pagecache_page)
		outside_reserve = 1;

4091
	get_page(old_page);
4092

4093 4094 4095 4096
	/*
	 * Drop page table lock as buddy allocator may be called. It will
	 * be acquired again before returning to the caller, as expected.
	 */
4097
	spin_unlock(ptl);
4098
	new_page = alloc_huge_page(vma, haddr, outside_reserve);
4099

4100
	if (IS_ERR(new_page)) {
4101 4102 4103 4104 4105 4106 4107 4108
		/*
		 * 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) {
4109
			put_page(old_page);
4110
			BUG_ON(huge_pte_none(pte));
4111
			unmap_ref_private(mm, vma, old_page, haddr);
4112 4113
			BUG_ON(huge_pte_none(pte));
			spin_lock(ptl);
4114
			ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4115 4116 4117 4118 4119 4120 4121 4122
			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;
4123 4124
		}

4125
		ret = vmf_error(PTR_ERR(new_page));
4126
		goto out_release_old;
4127 4128
	}

4129 4130 4131 4132
	/*
	 * When the original hugepage is shared one, it does not have
	 * anon_vma prepared.
	 */
4133
	if (unlikely(anon_vma_prepare(vma))) {
4134 4135
		ret = VM_FAULT_OOM;
		goto out_release_all;
4136
	}
4137

4138
	copy_user_huge_page(new_page, old_page, address, vma,
A
Andrea Arcangeli 已提交
4139
			    pages_per_huge_page(h));
N
Nick Piggin 已提交
4140
	__SetPageUptodate(new_page);
4141

4142
	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
4143
				haddr + huge_page_size(h));
4144
	mmu_notifier_invalidate_range_start(&range);
4145

4146
	/*
4147
	 * Retake the page table lock to check for racing updates
4148 4149
	 * before the page tables are altered
	 */
4150
	spin_lock(ptl);
4151
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4152
	if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
4153 4154
		ClearPagePrivate(new_page);

4155
		/* Break COW */
4156
		huge_ptep_clear_flush(vma, haddr, ptep);
4157
		mmu_notifier_invalidate_range(mm, range.start, range.end);
4158
		set_huge_pte_at(mm, haddr, ptep,
4159
				make_huge_pte(vma, new_page, 1));
4160
		page_remove_rmap(old_page, true);
4161
		hugepage_add_new_anon_rmap(new_page, vma, haddr);
4162
		set_page_huge_active(new_page);
4163 4164 4165
		/* Make the old page be freed below */
		new_page = old_page;
	}
4166
	spin_unlock(ptl);
4167
	mmu_notifier_invalidate_range_end(&range);
4168
out_release_all:
4169
	restore_reserve_on_error(h, vma, haddr, new_page);
4170
	put_page(new_page);
4171
out_release_old:
4172
	put_page(old_page);
4173

4174 4175
	spin_lock(ptl); /* Caller expects lock to be held */
	return ret;
4176 4177
}

4178
/* Return the pagecache page at a given address within a VMA */
4179 4180
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
			struct vm_area_struct *vma, unsigned long address)
4181 4182
{
	struct address_space *mapping;
4183
	pgoff_t idx;
4184 4185

	mapping = vma->vm_file->f_mapping;
4186
	idx = vma_hugecache_offset(h, vma, address);
4187 4188 4189 4190

	return find_lock_page(mapping, idx);
}

H
Hugh Dickins 已提交
4191 4192 4193 4194 4195
/*
 * 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
4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210
			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;
}

4211 4212 4213 4214 4215 4216 4217 4218 4219 4220 4221
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);

4222 4223 4224 4225 4226 4227
	/*
	 * set page dirty so that it will not be removed from cache/file
	 * by non-hugetlbfs specific code paths.
	 */
	set_page_dirty(page);

4228 4229 4230 4231 4232 4233
	spin_lock(&inode->i_lock);
	inode->i_blocks += blocks_per_huge_page(h);
	spin_unlock(&inode->i_lock);
	return 0;
}

4234 4235 4236 4237
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)
4238
{
4239
	struct hstate *h = hstate_vma(vma);
4240
	vm_fault_t ret = VM_FAULT_SIGBUS;
4241
	int anon_rmap = 0;
A
Adam Litke 已提交
4242 4243
	unsigned long size;
	struct page *page;
4244
	pte_t new_pte;
4245
	spinlock_t *ptl;
4246
	unsigned long haddr = address & huge_page_mask(h);
4247
	bool new_page = false;
A
Adam Litke 已提交
4248

4249 4250 4251
	/*
	 * 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
4252
	 * COW. Warn that such a situation has occurred as it may not be obvious
4253 4254
	 */
	if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
4255
		pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
4256
			   current->pid);
4257 4258 4259
		return ret;
	}

A
Adam Litke 已提交
4260
	/*
4261 4262 4263
	 * 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
4264
	 */
4265 4266 4267 4268
	size = i_size_read(mapping->host) >> huge_page_shift(h);
	if (idx >= size)
		goto out;

4269 4270 4271
retry:
	page = find_lock_page(mapping, idx);
	if (!page) {
4272 4273 4274 4275 4276 4277 4278
		/*
		 * Check for page in userfault range
		 */
		if (userfaultfd_missing(vma)) {
			u32 hash;
			struct vm_fault vmf = {
				.vma = vma,
4279
				.address = haddr,
4280 4281 4282 4283 4284 4285 4286 4287 4288 4289 4290
				.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
				 */
			};

			/*
4291 4292 4293
			 * hugetlb_fault_mutex and i_mmap_rwsem must be
			 * dropped before handling userfault.  Reacquire
			 * after handling fault to make calling code simpler.
4294
			 */
4295
			hash = hugetlb_fault_mutex_hash(mapping, idx);
4296
			mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4297
			i_mmap_unlock_read(mapping);
4298
			ret = handle_userfault(&vmf, VM_UFFD_MISSING);
4299
			i_mmap_lock_read(mapping);
4300 4301 4302 4303
			mutex_lock(&hugetlb_fault_mutex_table[hash]);
			goto out;
		}

4304
		page = alloc_huge_page(vma, haddr, 0);
4305
		if (IS_ERR(page)) {
4306 4307 4308 4309 4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321 4322 4323 4324
			/*
			 * 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);
4325
			ret = vmf_error(PTR_ERR(page));
4326 4327
			goto out;
		}
A
Andrea Arcangeli 已提交
4328
		clear_huge_page(page, address, pages_per_huge_page(h));
N
Nick Piggin 已提交
4329
		__SetPageUptodate(page);
4330
		new_page = true;
4331

4332
		if (vma->vm_flags & VM_MAYSHARE) {
4333
			int err = huge_add_to_page_cache(page, mapping, idx);
4334 4335 4336 4337 4338 4339
			if (err) {
				put_page(page);
				if (err == -EEXIST)
					goto retry;
				goto out;
			}
4340
		} else {
4341
			lock_page(page);
4342 4343 4344 4345
			if (unlikely(anon_vma_prepare(vma))) {
				ret = VM_FAULT_OOM;
				goto backout_unlocked;
			}
4346
			anon_rmap = 1;
4347
		}
4348
	} else {
4349 4350 4351 4352 4353 4354
		/*
		 * 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))) {
4355
			ret = VM_FAULT_HWPOISON |
4356
				VM_FAULT_SET_HINDEX(hstate_index(h));
4357 4358
			goto backout_unlocked;
		}
4359
	}
4360

4361 4362 4363 4364 4365 4366
	/*
	 * 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.
	 */
4367
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4368
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4369 4370 4371
			ret = VM_FAULT_OOM;
			goto backout_unlocked;
		}
4372
		/* Just decrements count, does not deallocate */
4373
		vma_end_reservation(h, vma, haddr);
4374
	}
4375

4376
	ptl = huge_pte_lock(h, mm, ptep);
N
Nick Piggin 已提交
4377
	ret = 0;
4378
	if (!huge_pte_none(huge_ptep_get(ptep)))
A
Adam Litke 已提交
4379 4380
		goto backout;

4381 4382
	if (anon_rmap) {
		ClearPagePrivate(page);
4383
		hugepage_add_new_anon_rmap(page, vma, haddr);
4384
	} else
4385
		page_dup_rmap(page, true);
4386 4387
	new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
				&& (vma->vm_flags & VM_SHARED)));
4388
	set_huge_pte_at(mm, haddr, ptep, new_pte);
4389

4390
	hugetlb_count_add(pages_per_huge_page(h), mm);
4391
	if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
4392
		/* Optimization, do the COW without a second fault */
4393
		ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
4394 4395
	}

4396
	spin_unlock(ptl);
4397 4398 4399 4400 4401 4402 4403 4404 4405

	/*
	 * 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
4406 4407
	unlock_page(page);
out:
4408
	return ret;
A
Adam Litke 已提交
4409 4410

backout:
4411
	spin_unlock(ptl);
4412
backout_unlocked:
A
Adam Litke 已提交
4413
	unlock_page(page);
4414
	restore_reserve_on_error(h, vma, haddr, page);
A
Adam Litke 已提交
4415 4416
	put_page(page);
	goto out;
4417 4418
}

4419
#ifdef CONFIG_SMP
4420
u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4421 4422 4423 4424
{
	unsigned long key[2];
	u32 hash;

4425 4426
	key[0] = (unsigned long) mapping;
	key[1] = idx;
4427

4428
	hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
4429 4430 4431 4432 4433 4434 4435 4436

	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.
 */
4437
u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
4438 4439 4440 4441 4442
{
	return 0;
}
#endif

4443
vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
4444
			unsigned long address, unsigned int flags)
4445
{
4446
	pte_t *ptep, entry;
4447
	spinlock_t *ptl;
4448
	vm_fault_t ret;
4449 4450
	u32 hash;
	pgoff_t idx;
4451
	struct page *page = NULL;
4452
	struct page *pagecache_page = NULL;
4453
	struct hstate *h = hstate_vma(vma);
4454
	struct address_space *mapping;
4455
	int need_wait_lock = 0;
4456
	unsigned long haddr = address & huge_page_mask(h);
4457

4458
	ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
4459
	if (ptep) {
4460 4461 4462 4463 4464
		/*
		 * 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.
		 */
4465
		entry = huge_ptep_get(ptep);
N
Naoya Horiguchi 已提交
4466
		if (unlikely(is_hugetlb_entry_migration(entry))) {
4467
			migration_entry_wait_huge(vma, mm, ptep);
N
Naoya Horiguchi 已提交
4468 4469
			return 0;
		} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
4470
			return VM_FAULT_HWPOISON_LARGE |
4471
				VM_FAULT_SET_HINDEX(hstate_index(h));
4472 4473
	}

4474 4475
	/*
	 * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
4476 4477 4478 4479
	 * 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.
4480 4481 4482 4483 4484
	 *
	 * 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.
	 */
4485
	mapping = vma->vm_file->f_mapping;
4486 4487 4488 4489 4490 4491
	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;
	}
4492

4493 4494 4495 4496 4497
	/*
	 * 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.
	 */
4498
	idx = vma_hugecache_offset(h, vma, haddr);
4499
	hash = hugetlb_fault_mutex_hash(mapping, idx);
4500
	mutex_lock(&hugetlb_fault_mutex_table[hash]);
4501

4502 4503
	entry = huge_ptep_get(ptep);
	if (huge_pte_none(entry)) {
4504
		ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
4505
		goto out_mutex;
4506
	}
4507

N
Nick Piggin 已提交
4508
	ret = 0;
4509

4510 4511 4512
	/*
	 * 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
4513 4514 4515
	 * an active hugepage in pagecache. This goto expects the 2nd page
	 * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
	 * properly handle it.
4516 4517 4518 4519
	 */
	if (!pte_present(entry))
		goto out_mutex;

4520 4521 4522 4523 4524 4525 4526 4527
	/*
	 * 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.
	 */
4528
	if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
4529
		if (vma_needs_reservation(h, vma, haddr) < 0) {
4530
			ret = VM_FAULT_OOM;
4531
			goto out_mutex;
4532
		}
4533
		/* Just decrements count, does not deallocate */
4534
		vma_end_reservation(h, vma, haddr);
4535

4536
		if (!(vma->vm_flags & VM_MAYSHARE))
4537
			pagecache_page = hugetlbfs_pagecache_page(h,
4538
								vma, haddr);
4539 4540
	}

4541 4542 4543 4544 4545 4546
	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;

4547 4548 4549 4550 4551 4552 4553
	/*
	 * 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)
4554 4555 4556 4557
		if (!trylock_page(page)) {
			need_wait_lock = 1;
			goto out_ptl;
		}
4558

4559
	get_page(page);
4560

4561
	if (flags & FAULT_FLAG_WRITE) {
4562
		if (!huge_pte_write(entry)) {
4563
			ret = hugetlb_cow(mm, vma, address, ptep,
4564
					  pagecache_page, ptl);
4565
			goto out_put_page;
4566
		}
4567
		entry = huge_pte_mkdirty(entry);
4568 4569
	}
	entry = pte_mkyoung(entry);
4570
	if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
4571
						flags & FAULT_FLAG_WRITE))
4572
		update_mmu_cache(vma, haddr, ptep);
4573 4574 4575 4576
out_put_page:
	if (page != pagecache_page)
		unlock_page(page);
	put_page(page);
4577 4578
out_ptl:
	spin_unlock(ptl);
4579 4580 4581 4582 4583

	if (pagecache_page) {
		unlock_page(pagecache_page);
		put_page(pagecache_page);
	}
4584
out_mutex:
4585
	mutex_unlock(&hugetlb_fault_mutex_table[hash]);
4586
	i_mmap_unlock_read(mapping);
4587 4588 4589 4590 4591 4592 4593 4594 4595
	/*
	 * 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);
4596
	return ret;
4597 4598
}

4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609
/*
 * 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)
{
4610 4611 4612
	struct address_space *mapping;
	pgoff_t idx;
	unsigned long size;
4613
	int vm_shared = dst_vma->vm_flags & VM_SHARED;
4614 4615 4616 4617 4618 4619 4620 4621 4622 4623 4624 4625 4626 4627
	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,
4628
						pages_per_huge_page(h), false);
4629

4630
		/* fallback to copy_from_user outside mmap_lock */
4631
		if (unlikely(ret)) {
4632
			ret = -ENOENT;
4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648
			*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);

4649 4650 4651
	mapping = dst_vma->vm_file->f_mapping;
	idx = vma_hugecache_offset(h, dst_vma, dst_addr);

4652 4653 4654 4655
	/*
	 * If shared, add to page cache
	 */
	if (vm_shared) {
4656 4657 4658 4659
		size = i_size_read(mapping->host) >> huge_page_shift(h);
		ret = -EFAULT;
		if (idx >= size)
			goto out_release_nounlock;
4660

4661 4662 4663 4664 4665 4666
		/*
		 * 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.
		 */
4667 4668 4669 4670 4671
		ret = huge_add_to_page_cache(page, mapping, idx);
		if (ret)
			goto out_release_nounlock;
	}

4672 4673 4674
	ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
	spin_lock(ptl);

4675 4676 4677 4678 4679 4680 4681 4682 4683 4684 4685 4686 4687 4688
	/*
	 * 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;

4689 4690 4691 4692
	ret = -EEXIST;
	if (!huge_pte_none(huge_ptep_get(dst_pte)))
		goto out_release_unlock;

4693 4694 4695 4696 4697 4698
	if (vm_shared) {
		page_dup_rmap(page, true);
	} else {
		ClearPagePrivate(page);
		hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
	}
4699 4700 4701 4702 4703 4704 4705 4706 4707 4708 4709 4710 4711 4712 4713 4714

	_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);
4715
	set_page_huge_active(page);
4716 4717
	if (vm_shared)
		unlock_page(page);
4718 4719 4720 4721 4722
	ret = 0;
out:
	return ret;
out_release_unlock:
	spin_unlock(ptl);
4723 4724
	if (vm_shared)
		unlock_page(page);
4725
out_release_nounlock:
4726 4727 4728 4729
	put_page(page);
	goto out;
}

4730 4731 4732
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,
4733
			 long i, unsigned int flags, int *locked)
D
David Gibson 已提交
4734
{
4735 4736
	unsigned long pfn_offset;
	unsigned long vaddr = *position;
4737
	unsigned long remainder = *nr_pages;
4738
	struct hstate *h = hstate_vma(vma);
4739
	int err = -EFAULT;
D
David Gibson 已提交
4740 4741

	while (vaddr < vma->vm_end && remainder) {
A
Adam Litke 已提交
4742
		pte_t *pte;
4743
		spinlock_t *ptl = NULL;
H
Hugh Dickins 已提交
4744
		int absent;
A
Adam Litke 已提交
4745
		struct page *page;
D
David Gibson 已提交
4746

4747 4748 4749 4750
		/*
		 * If we have a pending SIGKILL, don't keep faulting pages and
		 * potentially allocating memory.
		 */
4751
		if (fatal_signal_pending(current)) {
4752 4753 4754 4755
			remainder = 0;
			break;
		}

A
Adam Litke 已提交
4756 4757
		/*
		 * Some archs (sparc64, sh*) have multiple pte_ts to
H
Hugh Dickins 已提交
4758
		 * each hugepage.  We have to make sure we get the
A
Adam Litke 已提交
4759
		 * first, for the page indexing below to work.
4760 4761
		 *
		 * Note that page table lock is not held when pte is null.
A
Adam Litke 已提交
4762
		 */
4763 4764
		pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
				      huge_page_size(h));
4765 4766
		if (pte)
			ptl = huge_pte_lock(h, mm, pte);
H
Hugh Dickins 已提交
4767 4768 4769 4770
		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
4771 4772 4773 4774
		 * 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
4775
		 */
H
Hugh Dickins 已提交
4776 4777
		if (absent && (flags & FOLL_DUMP) &&
		    !hugetlbfs_pagecache_present(h, vma, vaddr)) {
4778 4779
			if (pte)
				spin_unlock(ptl);
H
Hugh Dickins 已提交
4780 4781 4782
			remainder = 0;
			break;
		}
D
David Gibson 已提交
4783

4784 4785 4786 4787 4788 4789 4790 4791 4792 4793 4794
		/*
		 * 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)) ||
4795 4796
		    ((flags & FOLL_WRITE) &&
		      !huge_pte_write(huge_ptep_get(pte)))) {
4797
			vm_fault_t ret;
4798
			unsigned int fault_flags = 0;
D
David Gibson 已提交
4799

4800 4801
			if (pte)
				spin_unlock(ptl);
4802 4803
			if (flags & FOLL_WRITE)
				fault_flags |= FAULT_FLAG_WRITE;
4804
			if (locked)
4805 4806
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_KILLABLE;
4807 4808 4809 4810
			if (flags & FOLL_NOWAIT)
				fault_flags |= FAULT_FLAG_ALLOW_RETRY |
					FAULT_FLAG_RETRY_NOWAIT;
			if (flags & FOLL_TRIED) {
4811 4812 4813 4814
				/*
				 * Note: FAULT_FLAG_ALLOW_RETRY and
				 * FAULT_FLAG_TRIED can co-exist
				 */
4815 4816 4817 4818
				fault_flags |= FAULT_FLAG_TRIED;
			}
			ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
			if (ret & VM_FAULT_ERROR) {
4819
				err = vm_fault_to_errno(ret, flags);
4820 4821 4822 4823
				remainder = 0;
				break;
			}
			if (ret & VM_FAULT_RETRY) {
4824
				if (locked &&
4825
				    !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
4826
					*locked = 0;
4827 4828 4829 4830 4831 4832 4833 4834 4835 4836 4837 4838 4839
				*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
4840 4841
		}

4842
		pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
4843
		page = pte_page(huge_ptep_get(pte));
4844

4845 4846 4847 4848 4849 4850 4851 4852 4853 4854 4855 4856 4857 4858
		/*
		 * 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;
		}

4859
same_page:
4860
		if (pages) {
H
Hugh Dickins 已提交
4861
			pages[i] = mem_map_offset(page, pfn_offset);
J
John Hubbard 已提交
4862 4863 4864 4865 4866 4867 4868 4869 4870 4871 4872 4873 4874 4875 4876 4877
			/*
			 * 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;
			}
4878
		}
D
David Gibson 已提交
4879 4880 4881 4882 4883

		if (vmas)
			vmas[i] = vma;

		vaddr += PAGE_SIZE;
4884
		++pfn_offset;
D
David Gibson 已提交
4885 4886
		--remainder;
		++i;
4887
		if (vaddr < vma->vm_end && remainder &&
4888
				pfn_offset < pages_per_huge_page(h)) {
4889 4890 4891 4892 4893 4894
			/*
			 * We use pfn_offset to avoid touching the pageframes
			 * of this compound page.
			 */
			goto same_page;
		}
4895
		spin_unlock(ptl);
D
David Gibson 已提交
4896
	}
4897
	*nr_pages = remainder;
4898 4899 4900 4901 4902
	/*
	 * 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
4903 4904
	*position = vaddr;

4905
	return i ? i : err;
D
David Gibson 已提交
4906
}
4907

4908 4909 4910 4911 4912 4913 4914 4915
#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

4916
unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
4917 4918 4919 4920 4921 4922
		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;
4923
	struct hstate *h = hstate_vma(vma);
4924
	unsigned long pages = 0;
4925
	bool shared_pmd = false;
4926
	struct mmu_notifier_range range;
4927 4928 4929

	/*
	 * In the case of shared PMDs, the area to flush could be beyond
4930
	 * start/end.  Set range.start/range.end to cover the maximum possible
4931 4932
	 * range if PMD sharing is possible.
	 */
4933 4934
	mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
				0, vma, mm, start, end);
4935
	adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
4936 4937

	BUG_ON(address >= end);
4938
	flush_cache_range(vma, range.start, range.end);
4939

4940
	mmu_notifier_invalidate_range_start(&range);
4941
	i_mmap_lock_write(vma->vm_file->f_mapping);
4942
	for (; address < end; address += huge_page_size(h)) {
4943
		spinlock_t *ptl;
4944
		ptep = huge_pte_offset(mm, address, huge_page_size(h));
4945 4946
		if (!ptep)
			continue;
4947
		ptl = huge_pte_lock(h, mm, ptep);
4948
		if (huge_pmd_unshare(mm, vma, &address, ptep)) {
4949
			pages++;
4950
			spin_unlock(ptl);
4951
			shared_pmd = true;
4952
			continue;
4953
		}
4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966
		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);
4967 4968
				set_huge_swap_pte_at(mm, address, ptep,
						     newpte, huge_page_size(h));
4969 4970 4971 4972 4973 4974
				pages++;
			}
			spin_unlock(ptl);
			continue;
		}
		if (!huge_pte_none(pte)) {
4975 4976 4977 4978
			pte_t old_pte;

			old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
			pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
4979
			pte = arch_make_huge_pte(pte, vma, NULL, 0);
4980
			huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
4981
			pages++;
4982
		}
4983
		spin_unlock(ptl);
4984
	}
4985
	/*
4986
	 * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
4987
	 * may have cleared our pud entry and done put_page on the page table:
4988
	 * once we release i_mmap_rwsem, another task can do the final put_page
4989 4990
	 * 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.
4991
	 */
4992
	if (shared_pmd)
4993
		flush_hugetlb_tlb_range(vma, range.start, range.end);
4994 4995
	else
		flush_hugetlb_tlb_range(vma, start, end);
4996 4997 4998 4999
	/*
	 * No need to call mmu_notifier_invalidate_range() we are downgrading
	 * page table protection not changing it to point to a new page.
	 *
5000
	 * See Documentation/vm/mmu_notifier.rst
5001
	 */
5002
	i_mmap_unlock_write(vma->vm_file->f_mapping);
5003
	mmu_notifier_invalidate_range_end(&range);
5004 5005

	return pages << h->order;
5006 5007
}

5008 5009
int hugetlb_reserve_pages(struct inode *inode,
					long from, long to,
5010
					struct vm_area_struct *vma,
5011
					vm_flags_t vm_flags)
5012
{
5013
	long ret, chg, add = -1;
5014
	struct hstate *h = hstate_inode(inode);
5015
	struct hugepage_subpool *spool = subpool_inode(inode);
5016
	struct resv_map *resv_map;
5017
	struct hugetlb_cgroup *h_cg = NULL;
5018
	long gbl_reserve, regions_needed = 0;
5019

5020 5021 5022 5023 5024 5025
	/* This should never happen */
	if (from > to) {
		VM_WARN(1, "%s called with a negative range\n", __func__);
		return -EINVAL;
	}

5026 5027 5028
	/*
	 * Only apply hugepage reservation if asked. At fault time, an
	 * attempt will be made for VM_NORESERVE to allocate a page
5029
	 * without using reserves
5030
	 */
5031
	if (vm_flags & VM_NORESERVE)
5032 5033
		return 0;

5034 5035 5036 5037 5038 5039
	/*
	 * 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
	 */
5040
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
5041 5042 5043 5044 5045
		/*
		 * 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).
		 */
5046
		resv_map = inode_resv_map(inode);
5047

5048
		chg = region_chg(resv_map, from, to, &regions_needed);
5049 5050

	} else {
5051
		/* Private mapping. */
5052
		resv_map = resv_map_alloc();
5053 5054 5055
		if (!resv_map)
			return -ENOMEM;

5056
		chg = to - from;
5057

5058 5059 5060 5061
		set_vma_resv_map(vma, resv_map);
		set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
	}

5062 5063 5064 5065
	if (chg < 0) {
		ret = chg;
		goto out_err;
	}
5066

5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081
	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);
	}

5082 5083 5084 5085 5086 5087 5088
	/*
	 * 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) {
5089
		ret = -ENOSPC;
5090
		goto out_uncharge_cgroup;
5091
	}
5092 5093

	/*
5094
	 * Check enough hugepages are available for the reservation.
5095
	 * Hand the pages back to the subpool if there are not
5096
	 */
5097
	ret = hugetlb_acct_memory(h, gbl_reserve);
K
Ken Chen 已提交
5098
	if (ret < 0) {
5099
		goto out_put_pages;
K
Ken Chen 已提交
5100
	}
5101 5102 5103 5104 5105 5106 5107 5108 5109 5110 5111 5112

	/*
	 * 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
	 */
5113
	if (!vma || vma->vm_flags & VM_MAYSHARE) {
5114
		add = region_add(resv_map, from, to, regions_needed, h, h_cg);
5115 5116 5117

		if (unlikely(add < 0)) {
			hugetlb_acct_memory(h, -gbl_reserve);
5118
			goto out_put_pages;
5119
		} else if (unlikely(chg > add)) {
5120 5121 5122 5123 5124 5125 5126 5127 5128
			/*
			 * 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;

5129 5130 5131 5132
			hugetlb_cgroup_uncharge_cgroup_rsvd(
				hstate_index(h),
				(chg - add) * pages_per_huge_page(h), h_cg);

5133 5134 5135 5136 5137
			rsv_adjust = hugepage_subpool_put_pages(spool,
								chg - add);
			hugetlb_acct_memory(h, -rsv_adjust);
		}
	}
5138
	return 0;
5139 5140 5141 5142 5143 5144
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);
5145
out_err:
5146
	if (!vma || vma->vm_flags & VM_MAYSHARE)
5147 5148 5149 5150 5151
		/* 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
5152 5153
	if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
		kref_put(&resv_map->refs, resv_map_release);
5154
	return ret;
5155 5156
}

5157 5158
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
								long freed)
5159
{
5160
	struct hstate *h = hstate_inode(inode);
5161
	struct resv_map *resv_map = inode_resv_map(inode);
5162
	long chg = 0;
5163
	struct hugepage_subpool *spool = subpool_inode(inode);
5164
	long gbl_reserve;
K
Ken Chen 已提交
5165

5166 5167 5168 5169
	/*
	 * Since this routine can be called in the evict inode path for all
	 * hugetlbfs inodes, resv_map could be NULL.
	 */
5170 5171 5172 5173 5174 5175 5176 5177 5178 5179 5180
	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
5181
	spin_lock(&inode->i_lock);
5182
	inode->i_blocks -= (blocks_per_huge_page(h) * freed);
K
Ken Chen 已提交
5183 5184
	spin_unlock(&inode->i_lock);

5185 5186 5187 5188 5189 5190
	/*
	 * 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);
5191 5192

	return 0;
5193
}
5194

5195 5196 5197 5198 5199 5200 5201 5202 5203 5204 5205
#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
5206 5207
	unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
	unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
5208 5209 5210 5211 5212 5213 5214 5215 5216 5217 5218 5219 5220

	/*
	 * 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;
}

5221
static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
5222 5223 5224 5225 5226 5227 5228
{
	unsigned long base = addr & PUD_MASK;
	unsigned long end = base + PUD_SIZE;

	/*
	 * check on proper vm_flags and page table alignment
	 */
5229
	if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
5230 5231
		return true;
	return false;
5232 5233
}

5234 5235 5236 5237 5238 5239 5240 5241
/*
 * 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)
{
5242
	unsigned long a_start, a_end;
5243 5244 5245 5246

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

5247 5248 5249
	/* Extend the range to be PUD aligned for a worst case scenario */
	a_start = ALIGN_DOWN(*start, PUD_SIZE);
	a_end = ALIGN(*end, PUD_SIZE);
5250

5251 5252 5253 5254 5255 5256
	/*
	 * Intersect the range with the vma range, since pmd sharing won't be
	 * across vma after all
	 */
	*start = max(vma->vm_start, a_start);
	*end = min(vma->vm_end, a_end);
5257 5258
}

5259 5260 5261 5262
/*
 * 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
5263 5264
 * code much cleaner.
 *
5265 5266 5267 5268 5269 5270 5271 5272 5273 5274
 * 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.
5275 5276 5277 5278 5279 5280 5281 5282 5283 5284 5285
 */
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;
5286
	spinlock_t *ptl;
5287 5288 5289 5290

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

5291
	i_mmap_assert_locked(mapping);
5292 5293 5294 5295 5296 5297
	vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
		if (svma == vma)
			continue;

		saddr = page_table_shareable(svma, vma, addr, idx);
		if (saddr) {
5298 5299
			spte = huge_pte_offset(svma->vm_mm, saddr,
					       vma_mmu_pagesize(svma));
5300 5301 5302 5303 5304 5305 5306 5307 5308 5309
			if (spte) {
				get_page(virt_to_page(spte));
				break;
			}
		}
	}

	if (!spte)
		goto out;

5310
	ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
5311
	if (pud_none(*pud)) {
5312 5313
		pud_populate(mm, pud,
				(pmd_t *)((unsigned long)spte & PAGE_MASK));
5314
		mm_inc_nr_pmds(mm);
5315
	} else {
5316
		put_page(virt_to_page(spte));
5317
	}
5318
	spin_unlock(ptl);
5319 5320 5321 5322 5323 5324 5325 5326 5327 5328 5329 5330
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.
 *
5331
 * Called with page table lock held and i_mmap_rwsem held in write mode.
5332 5333 5334 5335
 *
 * returns: 1 successfully unmapped a shared pte page
 *	    0 the underlying pte page is not shared, or it is the last user
 */
5336 5337
int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
					unsigned long *addr, pte_t *ptep)
5338 5339
{
	pgd_t *pgd = pgd_offset(mm, *addr);
5340 5341
	p4d_t *p4d = p4d_offset(pgd, *addr);
	pud_t *pud = pud_offset(p4d, *addr);
5342

5343
	i_mmap_assert_write_locked(vma->vm_file->f_mapping);
5344 5345 5346 5347 5348 5349
	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));
5350
	mm_dec_nr_pmds(mm);
5351 5352 5353
	*addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
	return 1;
}
5354 5355 5356 5357 5358 5359
#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;
}
5360

5361 5362
int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
				unsigned long *addr, pte_t *ptep)
5363 5364 5365
{
	return 0;
}
5366 5367 5368 5369 5370

void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
				unsigned long *start, unsigned long *end)
{
}
5371
#define want_pmd_share()	(0)
5372 5373
#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

5374 5375 5376 5377 5378
#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
pte_t *huge_pte_alloc(struct mm_struct *mm,
			unsigned long addr, unsigned long sz)
{
	pgd_t *pgd;
5379
	p4d_t *p4d;
5380 5381 5382 5383
	pud_t *pud;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
5384 5385 5386
	p4d = p4d_alloc(mm, pgd, addr);
	if (!p4d)
		return NULL;
5387
	pud = pud_alloc(mm, p4d, addr);
5388 5389 5390 5391 5392 5393 5394 5395 5396 5397 5398
	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);
		}
	}
5399
	BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
5400 5401 5402 5403

	return pte;
}

5404 5405 5406 5407
/*
 * huge_pte_offset() - Walk the page table to resolve the hugepage
 * entry at address @addr
 *
5408 5409
 * Return: Pointer to page table entry (PUD or PMD) for
 * address @addr, or NULL if a !p*d_present() entry is encountered and the
5410 5411 5412
 * size @sz doesn't match the hugepage size at this level of the page
 * table.
 */
5413 5414
pte_t *huge_pte_offset(struct mm_struct *mm,
		       unsigned long addr, unsigned long sz)
5415 5416
{
	pgd_t *pgd;
5417
	p4d_t *p4d;
5418 5419
	pud_t *pud;
	pmd_t *pmd;
5420 5421

	pgd = pgd_offset(mm, addr);
5422 5423 5424 5425 5426
	if (!pgd_present(*pgd))
		return NULL;
	p4d = p4d_offset(pgd, addr);
	if (!p4d_present(*p4d))
		return NULL;
5427

5428
	pud = pud_offset(p4d, addr);
5429 5430
	if (sz == PUD_SIZE)
		/* must be pud huge, non-present or none */
5431
		return (pte_t *)pud;
5432
	if (!pud_present(*pud))
5433
		return NULL;
5434
	/* must have a valid entry and size to go further */
5435

5436 5437 5438
	pmd = pmd_offset(pud, addr);
	/* must be pmd huge, non-present or none */
	return (pte_t *)pmd;
5439 5440
}

5441 5442 5443 5444 5445 5446 5447 5448 5449 5450 5451 5452 5453
#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);
}

5454 5455 5456 5457 5458 5459 5460 5461
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;
}

5462
struct page * __weak
5463
follow_huge_pmd(struct mm_struct *mm, unsigned long address,
5464
		pmd_t *pmd, int flags)
5465
{
5466 5467
	struct page *page = NULL;
	spinlock_t *ptl;
5468
	pte_t pte;
J
John Hubbard 已提交
5469 5470 5471 5472 5473 5474

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

5475 5476 5477 5478 5479 5480 5481 5482 5483
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;
5484 5485
	pte = huge_ptep_get((pte_t *)pmd);
	if (pte_present(pte)) {
5486
		page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
J
John Hubbard 已提交
5487 5488 5489 5490 5491 5492 5493 5494 5495 5496 5497 5498
		/*
		 * 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;
		}
5499
	} else {
5500
		if (is_hugetlb_entry_migration(pte)) {
5501 5502 5503 5504 5505 5506 5507 5508 5509 5510 5511
			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);
5512 5513 5514
	return page;
}

5515
struct page * __weak
5516
follow_huge_pud(struct mm_struct *mm, unsigned long address,
5517
		pud_t *pud, int flags)
5518
{
J
John Hubbard 已提交
5519
	if (flags & (FOLL_GET | FOLL_PIN))
5520
		return NULL;
5521

5522
	return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
5523 5524
}

5525 5526 5527
struct page * __weak
follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
{
J
John Hubbard 已提交
5528
	if (flags & (FOLL_GET | FOLL_PIN))
5529 5530 5531 5532 5533
		return NULL;

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

5534 5535
bool isolate_huge_page(struct page *page, struct list_head *list)
{
5536 5537
	bool ret = true;

5538
	VM_BUG_ON_PAGE(!PageHead(page), page);
5539
	spin_lock(&hugetlb_lock);
5540 5541 5542 5543 5544
	if (!page_huge_active(page) || !get_page_unless_zero(page)) {
		ret = false;
		goto unlock;
	}
	clear_page_huge_active(page);
5545
	list_move_tail(&page->lru, list);
5546
unlock:
5547
	spin_unlock(&hugetlb_lock);
5548
	return ret;
5549 5550 5551 5552
}

void putback_active_hugepage(struct page *page)
{
5553
	VM_BUG_ON_PAGE(!PageHead(page), page);
5554
	spin_lock(&hugetlb_lock);
5555
	set_page_huge_active(page);
5556 5557 5558 5559
	list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
	spin_unlock(&hugetlb_lock);
	put_page(page);
}
5560 5561 5562 5563 5564 5565 5566 5567 5568 5569 5570 5571 5572 5573 5574 5575 5576 5577 5578 5579 5580 5581 5582 5583 5584 5585 5586 5587 5588 5589 5590 5591 5592

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);
	}
}
5593 5594 5595 5596 5597 5598 5599 5600 5601 5602 5603 5604 5605 5606 5607 5608 5609 5610 5611 5612 5613 5614 5615 5616 5617 5618 5619 5620 5621 5622 5623 5624 5625 5626 5627 5628 5629 5630 5631

#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;
5632
		char name[CMA_MAX_NAME];
5633 5634 5635 5636

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

5637
		snprintf(name, sizeof(name), "hugetlb%d", nid);
5638
		res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
5639
						 0, false, name,
5640 5641 5642 5643 5644 5645 5646 5647 5648 5649 5650 5651 5652 5653 5654 5655 5656 5657 5658 5659 5660 5661 5662 5663 5664
						 &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 */