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-rw-r--r--mm/hugetlb.c2980
1 files changed, 2980 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
new file mode 100644
index 00000000..05f8fd42
--- /dev/null
+++ b/mm/hugetlb.c
@@ -0,0 +1,2980 @@
+/*
+ * Generic hugetlb support.
+ * (C) William Irwin, April 2004
+ */
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/seq_file.h>
+#include <linux/sysctl.h>
+#include <linux/highmem.h>
+#include <linux/mmu_notifier.h>
+#include <linux/nodemask.h>
+#include <linux/pagemap.h>
+#include <linux/mempolicy.h>
+#include <linux/cpuset.h>
+#include <linux/mutex.h>
+#include <linux/bootmem.h>
+#include <linux/sysfs.h>
+#include <linux/slab.h>
+#include <linux/rmap.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/io.h>
+
+#include <linux/hugetlb.h>
+#include <linux/node.h>
+#include "internal.h"
+
+const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
+static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
+unsigned long hugepages_treat_as_movable;
+
+static int max_hstate;
+unsigned int default_hstate_idx;
+struct hstate hstates[HUGE_MAX_HSTATE];
+
+__initdata LIST_HEAD(huge_boot_pages);
+
+/* for command line parsing */
+static struct hstate * __initdata parsed_hstate;
+static unsigned long __initdata default_hstate_max_huge_pages;
+static unsigned long __initdata default_hstate_size;
+
+#define for_each_hstate(h) \
+ for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
+
+/*
+ * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
+ */
+static DEFINE_SPINLOCK(hugetlb_lock);
+
+/*
+ * Region tracking -- allows tracking of reservations and instantiated pages
+ * across the pages in a mapping.
+ *
+ * The region data structures are protected by a combination of the mmap_sem
+ * and the hugetlb_instantion_mutex. To access or modify a region the caller
+ * must either hold the mmap_sem for write, or the mmap_sem for read and
+ * the hugetlb_instantiation mutex:
+ *
+ * down_write(&mm->mmap_sem);
+ * or
+ * down_read(&mm->mmap_sem);
+ * mutex_lock(&hugetlb_instantiation_mutex);
+ */
+struct file_region {
+ struct list_head link;
+ long from;
+ long to;
+};
+
+static long region_add(struct list_head *head, long f, long t)
+{
+ struct file_region *rg, *nrg, *trg;
+
+ /* Locate the region we are either in or before. */
+ list_for_each_entry(rg, head, link)
+ if (f <= rg->to)
+ break;
+
+ /* Round our left edge to the current segment if it encloses us. */
+ if (f > rg->from)
+ f = rg->from;
+
+ /* Check for and consume any regions we now overlap with. */
+ nrg = rg;
+ list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
+ if (&rg->link == head)
+ break;
+ if (rg->from > t)
+ break;
+
+ /* If this area reaches higher then extend our area to
+ * include it completely. If this is not the first area
+ * which we intend to reuse, free it. */
+ if (rg->to > t)
+ t = rg->to;
+ if (rg != nrg) {
+ list_del(&rg->link);
+ kfree(rg);
+ }
+ }
+ nrg->from = f;
+ nrg->to = t;
+ return 0;
+}
+
+static long region_chg(struct list_head *head, long f, long t)
+{
+ struct file_region *rg, *nrg;
+ long chg = 0;
+
+ /* Locate the region we are before or in. */
+ list_for_each_entry(rg, head, link)
+ if (f <= rg->to)
+ break;
+
+ /* If we are below the current region then a new region is required.
+ * Subtle, allocate a new region at the position but make it zero
+ * size such that we can guarantee to record the reservation. */
+ if (&rg->link == head || t < rg->from) {
+ nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
+ if (!nrg)
+ return -ENOMEM;
+ nrg->from = f;
+ nrg->to = f;
+ INIT_LIST_HEAD(&nrg->link);
+ list_add(&nrg->link, rg->link.prev);
+
+ return t - f;
+ }
+
+ /* Round our left edge to the current segment if it encloses us. */
+ if (f > rg->from)
+ f = rg->from;
+ chg = t - f;
+
+ /* Check for and consume any regions we now overlap with. */
+ list_for_each_entry(rg, rg->link.prev, link) {
+ if (&rg->link == head)
+ break;
+ if (rg->from > t)
+ return chg;
+
+ /* We overlap with this area, if it extends further than
+ * us then we must extend ourselves. Account for its
+ * existing reservation. */
+ if (rg->to > t) {
+ chg += rg->to - t;
+ t = rg->to;
+ }
+ chg -= rg->to - rg->from;
+ }
+ return chg;
+}
+
+static long region_truncate(struct list_head *head, long end)
+{
+ struct file_region *rg, *trg;
+ long chg = 0;
+
+ /* Locate the region we are either in or before. */
+ list_for_each_entry(rg, head, link)
+ if (end <= rg->to)
+ break;
+ if (&rg->link == head)
+ return 0;
+
+ /* If we are in the middle of a region then adjust it. */
+ if (end > rg->from) {
+ chg = rg->to - end;
+ rg->to = end;
+ rg = list_entry(rg->link.next, typeof(*rg), link);
+ }
+
+ /* Drop any remaining regions. */
+ list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
+ if (&rg->link == head)
+ break;
+ chg += rg->to - rg->from;
+ list_del(&rg->link);
+ kfree(rg);
+ }
+ return chg;
+}
+
+static long region_count(struct list_head *head, long f, long t)
+{
+ struct file_region *rg;
+ long chg = 0;
+
+ /* Locate each segment we overlap with, and count that overlap. */
+ list_for_each_entry(rg, head, link) {
+ int seg_from;
+ int seg_to;
+
+ 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;
+ }
+
+ return chg;
+}
+
+/*
+ * Convert the address within this vma to the page offset within
+ * the mapping, in pagecache page units; huge pages here.
+ */
+static pgoff_t vma_hugecache_offset(struct hstate *h,
+ struct vm_area_struct *vma, unsigned long address)
+{
+ return ((address - vma->vm_start) >> huge_page_shift(h)) +
+ (vma->vm_pgoff >> huge_page_order(h));
+}
+
+pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
+ unsigned long address)
+{
+ return vma_hugecache_offset(hstate_vma(vma), vma, address);
+}
+
+/*
+ * 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)
+{
+ struct hstate *hstate;
+
+ if (!is_vm_hugetlb_page(vma))
+ return PAGE_SIZE;
+
+ hstate = hstate_vma(vma);
+
+ return 1UL << (hstate->order + PAGE_SHIFT);
+}
+EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
+
+/*
+ * 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
+ * architectures where it differs, an architecture-specific version of this
+ * function is required.
+ */
+#ifndef vma_mmu_pagesize
+unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
+{
+ return vma_kernel_pagesize(vma);
+}
+#endif
+
+/*
+ * 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)
+#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
+
+/*
+ * 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.
+ *
+ * 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.
+ */
+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;
+}
+
+struct resv_map {
+ struct kref refs;
+ struct list_head regions;
+};
+
+static struct resv_map *resv_map_alloc(void)
+{
+ struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
+ if (!resv_map)
+ return NULL;
+
+ kref_init(&resv_map->refs);
+ INIT_LIST_HEAD(&resv_map->regions);
+
+ return resv_map;
+}
+
+static void resv_map_release(struct kref *ref)
+{
+ struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
+
+ /* Clear out any active regions before we release the map. */
+ region_truncate(&resv_map->regions, 0);
+ kfree(resv_map);
+}
+
+static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
+{
+ VM_BUG_ON(!is_vm_hugetlb_page(vma));
+ if (!(vma->vm_flags & VM_MAYSHARE))
+ return (struct resv_map *)(get_vma_private_data(vma) &
+ ~HPAGE_RESV_MASK);
+ return NULL;
+}
+
+static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
+{
+ VM_BUG_ON(!is_vm_hugetlb_page(vma));
+ VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
+
+ set_vma_private_data(vma, (get_vma_private_data(vma) &
+ HPAGE_RESV_MASK) | (unsigned long)map);
+}
+
+static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
+{
+ VM_BUG_ON(!is_vm_hugetlb_page(vma));
+ VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
+
+ set_vma_private_data(vma, get_vma_private_data(vma) | flags);
+}
+
+static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
+{
+ VM_BUG_ON(!is_vm_hugetlb_page(vma));
+
+ return (get_vma_private_data(vma) & flag) != 0;
+}
+
+/* Decrement the reserved pages in the hugepage pool by one */
+static void decrement_hugepage_resv_vma(struct hstate *h,
+ struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & VM_NORESERVE)
+ return;
+
+ if (vma->vm_flags & VM_MAYSHARE) {
+ /* Shared mappings always use reserves */
+ h->resv_huge_pages--;
+ } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
+ /*
+ * Only the process that called mmap() has reserves for
+ * private mappings.
+ */
+ h->resv_huge_pages--;
+ }
+}
+
+/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
+void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
+{
+ VM_BUG_ON(!is_vm_hugetlb_page(vma));
+ if (!(vma->vm_flags & VM_MAYSHARE))
+ vma->vm_private_data = (void *)0;
+}
+
+/* Returns true if the VMA has associated reserve pages */
+static int vma_has_reserves(struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & VM_MAYSHARE)
+ return 1;
+ if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
+ return 1;
+ return 0;
+}
+
+static void copy_gigantic_page(struct page *dst, struct page *src)
+{
+ int i;
+ struct hstate *h = page_hstate(src);
+ struct page *dst_base = dst;
+ struct page *src_base = src;
+
+ for (i = 0; i < pages_per_huge_page(h); ) {
+ cond_resched();
+ copy_highpage(dst, src);
+
+ i++;
+ dst = mem_map_next(dst, dst_base, i);
+ src = mem_map_next(src, src_base, i);
+ }
+}
+
+void copy_huge_page(struct page *dst, struct page *src)
+{
+ int i;
+ struct hstate *h = page_hstate(src);
+
+ if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
+ copy_gigantic_page(dst, src);
+ return;
+ }
+
+ might_sleep();
+ for (i = 0; i < pages_per_huge_page(h); i++) {
+ cond_resched();
+ copy_highpage(dst + i, src + i);
+ }
+}
+
+static void enqueue_huge_page(struct hstate *h, struct page *page)
+{
+ int nid = page_to_nid(page);
+ list_add(&page->lru, &h->hugepage_freelists[nid]);
+ h->free_huge_pages++;
+ h->free_huge_pages_node[nid]++;
+}
+
+static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
+{
+ struct page *page;
+
+ if (list_empty(&h->hugepage_freelists[nid]))
+ return NULL;
+ page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
+ list_del(&page->lru);
+ set_page_refcounted(page);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[nid]--;
+ return page;
+}
+
+static struct page *dequeue_huge_page_vma(struct hstate *h,
+ struct vm_area_struct *vma,
+ unsigned long address, int avoid_reserve)
+{
+ struct page *page = NULL;
+ struct mempolicy *mpol;
+ nodemask_t *nodemask;
+ struct zonelist *zonelist;
+ struct zone *zone;
+ struct zoneref *z;
+
+ get_mems_allowed();
+ zonelist = huge_zonelist(vma, address,
+ htlb_alloc_mask, &mpol, &nodemask);
+ /*
+ * 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
+ */
+ if (!vma_has_reserves(vma) &&
+ h->free_huge_pages - h->resv_huge_pages == 0)
+ goto err;
+
+ /* If reserves cannot be used, ensure enough pages are in the pool */
+ if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
+ goto err;
+
+ for_each_zone_zonelist_nodemask(zone, z, zonelist,
+ MAX_NR_ZONES - 1, nodemask) {
+ if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
+ page = dequeue_huge_page_node(h, zone_to_nid(zone));
+ if (page) {
+ if (!avoid_reserve)
+ decrement_hugepage_resv_vma(h, vma);
+ break;
+ }
+ }
+ }
+err:
+ mpol_cond_put(mpol);
+ put_mems_allowed();
+ return page;
+}
+
+static void update_and_free_page(struct hstate *h, struct page *page)
+{
+ int i;
+
+ VM_BUG_ON(h->order >= MAX_ORDER);
+
+ h->nr_huge_pages--;
+ h->nr_huge_pages_node[page_to_nid(page)]--;
+ for (i = 0; i < pages_per_huge_page(h); i++) {
+ page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
+ 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
+ 1 << PG_private | 1<< PG_writeback);
+ }
+ set_compound_page_dtor(page, NULL);
+ set_page_refcounted(page);
+ arch_release_hugepage(page);
+ __free_pages(page, huge_page_order(h));
+}
+
+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;
+}
+
+static void free_huge_page(struct page *page)
+{
+ /*
+ * Can't pass hstate in here because it is called from the
+ * compound page destructor.
+ */
+ struct hstate *h = page_hstate(page);
+ int nid = page_to_nid(page);
+ struct address_space *mapping;
+
+ mapping = (struct address_space *) page_private(page);
+ set_page_private(page, 0);
+ page->mapping = NULL;
+ BUG_ON(page_count(page));
+ BUG_ON(page_mapcount(page));
+ INIT_LIST_HEAD(&page->lru);
+
+ spin_lock(&hugetlb_lock);
+ if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
+ update_and_free_page(h, page);
+ h->surplus_huge_pages--;
+ h->surplus_huge_pages_node[nid]--;
+ } else {
+ enqueue_huge_page(h, page);
+ }
+ spin_unlock(&hugetlb_lock);
+ if (mapping)
+ hugetlb_put_quota(mapping, 1);
+}
+
+static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
+{
+ set_compound_page_dtor(page, free_huge_page);
+ spin_lock(&hugetlb_lock);
+ h->nr_huge_pages++;
+ h->nr_huge_pages_node[nid]++;
+ spin_unlock(&hugetlb_lock);
+ put_page(page); /* free it into the hugepage allocator */
+}
+
+static void prep_compound_gigantic_page(struct page *page, unsigned long order)
+{
+ 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);
+ __SetPageHead(page);
+ for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
+ __SetPageTail(p);
+ set_page_count(p, 0);
+ p->first_page = page;
+ }
+}
+
+int PageHuge(struct page *page)
+{
+ compound_page_dtor *dtor;
+
+ if (!PageCompound(page))
+ return 0;
+
+ page = compound_head(page);
+ dtor = get_compound_page_dtor(page);
+
+ return dtor == free_huge_page;
+}
+
+EXPORT_SYMBOL_GPL(PageHuge);
+
+static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
+{
+ struct page *page;
+
+ if (h->order >= MAX_ORDER)
+ return NULL;
+
+ page = alloc_pages_exact_node(nid,
+ htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
+ __GFP_REPEAT|__GFP_NOWARN,
+ huge_page_order(h));
+ if (page) {
+ if (arch_prepare_hugepage(page)) {
+ __free_pages(page, huge_page_order(h));
+ return NULL;
+ }
+ prep_new_huge_page(h, page, nid);
+ }
+
+ return page;
+}
+
+/*
+ * 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)
+{
+ nid = next_node(nid, *nodes_allowed);
+ if (nid == MAX_NUMNODES)
+ nid = first_node(*nodes_allowed);
+ 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;
+}
+
+static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
+{
+ struct page *page;
+ int start_nid;
+ int next_nid;
+ int ret = 0;
+
+ start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
+ next_nid = start_nid;
+
+ do {
+ page = alloc_fresh_huge_page_node(h, next_nid);
+ if (page) {
+ ret = 1;
+ break;
+ }
+ next_nid = hstate_next_node_to_alloc(h, nodes_allowed);
+ } while (next_nid != start_nid);
+
+ if (ret)
+ count_vm_event(HTLB_BUDDY_PGALLOC);
+ else
+ count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
+
+ return ret;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * 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.
+ */
+static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
+ bool acct_surplus)
+{
+ int start_nid;
+ int next_nid;
+ int ret = 0;
+
+ start_nid = hstate_next_node_to_free(h, nodes_allowed);
+ next_nid = start_nid;
+
+ do {
+ /*
+ * If we're returning unused surplus pages, only examine
+ * nodes with surplus pages.
+ */
+ if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
+ !list_empty(&h->hugepage_freelists[next_nid])) {
+ struct page *page =
+ list_entry(h->hugepage_freelists[next_nid].next,
+ struct page, lru);
+ list_del(&page->lru);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[next_nid]--;
+ if (acct_surplus) {
+ h->surplus_huge_pages--;
+ h->surplus_huge_pages_node[next_nid]--;
+ }
+ update_and_free_page(h, page);
+ ret = 1;
+ break;
+ }
+ next_nid = hstate_next_node_to_free(h, nodes_allowed);
+ } while (next_nid != start_nid);
+
+ return ret;
+}
+
+static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
+{
+ struct page *page;
+ unsigned int r_nid;
+
+ if (h->order >= MAX_ORDER)
+ return NULL;
+
+ /*
+ * Assume we will successfully allocate the surplus page to
+ * prevent racing processes from causing the surplus to exceed
+ * overcommit
+ *
+ * This however introduces a different race, where a process B
+ * tries to grow the static hugepage pool while alloc_pages() is
+ * called by process A. B will only examine the per-node
+ * counters in determining if surplus huge pages can be
+ * converted to normal huge pages in adjust_pool_surplus(). A
+ * won't be able to increment the per-node counter, until the
+ * lock is dropped by B, but B doesn't drop hugetlb_lock until
+ * no more huge pages can be converted from surplus to normal
+ * state (and doesn't try to convert again). Thus, we have a
+ * case where a surplus huge page exists, the pool is grown, and
+ * the surplus huge page still exists after, even though it
+ * should just have been converted to a normal huge page. This
+ * does not leak memory, though, as the hugepage will be freed
+ * once it is out of use. It also does not allow the counters to
+ * go out of whack in adjust_pool_surplus() as we don't modify
+ * the node values until we've gotten the hugepage and only the
+ * per-node value is checked there.
+ */
+ spin_lock(&hugetlb_lock);
+ if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
+ spin_unlock(&hugetlb_lock);
+ return NULL;
+ } else {
+ h->nr_huge_pages++;
+ h->surplus_huge_pages++;
+ }
+ spin_unlock(&hugetlb_lock);
+
+ if (nid == NUMA_NO_NODE)
+ page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
+ __GFP_REPEAT|__GFP_NOWARN,
+ huge_page_order(h));
+ else
+ page = alloc_pages_exact_node(nid,
+ htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
+ __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
+
+ if (page && arch_prepare_hugepage(page)) {
+ __free_pages(page, huge_page_order(h));
+ return NULL;
+ }
+
+ spin_lock(&hugetlb_lock);
+ if (page) {
+ r_nid = page_to_nid(page);
+ set_compound_page_dtor(page, free_huge_page);
+ /*
+ * We incremented the global counters already
+ */
+ h->nr_huge_pages_node[r_nid]++;
+ h->surplus_huge_pages_node[r_nid]++;
+ __count_vm_event(HTLB_BUDDY_PGALLOC);
+ } else {
+ h->nr_huge_pages--;
+ h->surplus_huge_pages--;
+ __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
+ }
+ spin_unlock(&hugetlb_lock);
+
+ return page;
+}
+
+/*
+ * This allocation function is useful in the context where vma is irrelevant.
+ * E.g. soft-offlining uses this function because it only cares physical
+ * address of error page.
+ */
+struct page *alloc_huge_page_node(struct hstate *h, int nid)
+{
+ struct page *page;
+
+ spin_lock(&hugetlb_lock);
+ page = dequeue_huge_page_node(h, nid);
+ spin_unlock(&hugetlb_lock);
+
+ if (!page)
+ page = alloc_buddy_huge_page(h, nid);
+
+ return page;
+}
+
+/*
+ * Increase the hugetlb pool such that it can accommodate a reservation
+ * of size 'delta'.
+ */
+static int gather_surplus_pages(struct hstate *h, int delta)
+{
+ struct list_head surplus_list;
+ struct page *page, *tmp;
+ int ret, i;
+ int needed, allocated;
+
+ needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
+ if (needed <= 0) {
+ h->resv_huge_pages += delta;
+ return 0;
+ }
+
+ allocated = 0;
+ INIT_LIST_HEAD(&surplus_list);
+
+ ret = -ENOMEM;
+retry:
+ spin_unlock(&hugetlb_lock);
+ for (i = 0; i < needed; i++) {
+ page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
+ if (!page)
+ /*
+ * We were not able to allocate enough pages to
+ * satisfy the entire reservation so we free what
+ * we've allocated so far.
+ */
+ goto free;
+
+ list_add(&page->lru, &surplus_list);
+ }
+ allocated += needed;
+
+ /*
+ * 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);
+ needed = (h->resv_huge_pages + delta) -
+ (h->free_huge_pages + allocated);
+ if (needed > 0)
+ goto retry;
+
+ /*
+ * The surplus_list now contains _at_least_ the number of extra pages
+ * needed to accommodate the reservation. Add the appropriate number
+ * of pages to the hugetlb pool and free the extras back to the buddy
+ * 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.
+ */
+ needed += allocated;
+ h->resv_huge_pages += delta;
+ ret = 0;
+
+ /* Free the needed pages to the hugetlb pool */
+ list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
+ if ((--needed) < 0)
+ break;
+ list_del(&page->lru);
+ /*
+ * This page is now managed by the hugetlb allocator and has
+ * no users -- drop the buddy allocator's reference.
+ */
+ put_page_testzero(page);
+ VM_BUG_ON(page_count(page));
+ enqueue_huge_page(h, page);
+ }
+ spin_unlock(&hugetlb_lock);
+
+ /* Free unnecessary surplus pages to the buddy allocator */
+free:
+ if (!list_empty(&surplus_list)) {
+ list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
+ list_del(&page->lru);
+ put_page(page);
+ }
+ }
+ spin_lock(&hugetlb_lock);
+
+ return ret;
+}
+
+/*
+ * When releasing a hugetlb pool reservation, any surplus pages that were
+ * allocated to satisfy the reservation must be explicitly freed if they were
+ * never used.
+ * Called with hugetlb_lock held.
+ */
+static void return_unused_surplus_pages(struct hstate *h,
+ unsigned long unused_resv_pages)
+{
+ unsigned long nr_pages;
+
+ /* Uncommit the reservation */
+ h->resv_huge_pages -= unused_resv_pages;
+
+ /* Cannot return gigantic pages currently */
+ if (h->order >= MAX_ORDER)
+ return;
+
+ nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
+
+ /*
+ * We want to release as many surplus pages as possible, spread
+ * evenly across all nodes with memory. Iterate across these nodes
+ * until we can no longer free unreserved surplus pages. This occurs
+ * when the nodes with surplus pages have no free pages.
+ * free_pool_huge_page() will balance the the freed pages across the
+ * on-line nodes with memory and will handle the hstate accounting.
+ */
+ while (nr_pages--) {
+ if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
+ break;
+ }
+}
+
+/*
+ * Determine if the huge page at addr within the vma has an associated
+ * reservation. Where it does not we will need to logically increase
+ * reservation and actually increase quota before an allocation can occur.
+ * Where any new reservation would be required the reservation change is
+ * prepared, but not committed. Once the page has been quota'd allocated
+ * an instantiated the change should be committed via vma_commit_reservation.
+ * No action is required on failure.
+ */
+static long vma_needs_reservation(struct hstate *h,
+ struct vm_area_struct *vma, unsigned long addr)
+{
+ struct address_space *mapping = vma->vm_file->f_mapping;
+ struct inode *inode = mapping->host;
+
+ if (vma->vm_flags & VM_MAYSHARE) {
+ pgoff_t idx = vma_hugecache_offset(h, vma, addr);
+ return region_chg(&inode->i_mapping->private_list,
+ idx, idx + 1);
+
+ } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
+ return 1;
+
+ } else {
+ long err;
+ pgoff_t idx = vma_hugecache_offset(h, vma, addr);
+ struct resv_map *reservations = vma_resv_map(vma);
+
+ err = region_chg(&reservations->regions, idx, idx + 1);
+ if (err < 0)
+ return err;
+ return 0;
+ }
+}
+static void vma_commit_reservation(struct hstate *h,
+ struct vm_area_struct *vma, unsigned long addr)
+{
+ struct address_space *mapping = vma->vm_file->f_mapping;
+ struct inode *inode = mapping->host;
+
+ if (vma->vm_flags & VM_MAYSHARE) {
+ pgoff_t idx = vma_hugecache_offset(h, vma, addr);
+ region_add(&inode->i_mapping->private_list, idx, idx + 1);
+
+ } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
+ pgoff_t idx = vma_hugecache_offset(h, vma, addr);
+ struct resv_map *reservations = vma_resv_map(vma);
+
+ /* Mark this page used in the map. */
+ region_add(&reservations->regions, idx, idx + 1);
+ }
+}
+
+static struct page *alloc_huge_page(struct vm_area_struct *vma,
+ unsigned long addr, int avoid_reserve)
+{
+ struct hstate *h = hstate_vma(vma);
+ struct page *page;
+ struct address_space *mapping = vma->vm_file->f_mapping;
+ struct inode *inode = mapping->host;
+ long chg;
+
+ /*
+ * Processes that did not create the mapping will have no reserves and
+ * will not have accounted against quota. Check that the quota can be
+ * made before satisfying the allocation
+ * MAP_NORESERVE mappings may also need pages and quota allocated
+ * if no reserve mapping overlaps.
+ */
+ chg = vma_needs_reservation(h, vma, addr);
+ if (chg < 0)
+ return ERR_PTR(-VM_FAULT_OOM);
+ if (chg)
+ if (hugetlb_get_quota(inode->i_mapping, chg))
+ return ERR_PTR(-VM_FAULT_SIGBUS);
+
+ spin_lock(&hugetlb_lock);
+ page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
+ spin_unlock(&hugetlb_lock);
+
+ if (!page) {
+ page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
+ if (!page) {
+ hugetlb_put_quota(inode->i_mapping, chg);
+ return ERR_PTR(-VM_FAULT_SIGBUS);
+ }
+ }
+
+ set_page_private(page, (unsigned long) mapping);
+
+ vma_commit_reservation(h, vma, addr);
+
+ return page;
+}
+
+int __weak alloc_bootmem_huge_page(struct hstate *h)
+{
+ struct huge_bootmem_page *m;
+ int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
+
+ while (nr_nodes) {
+ void *addr;
+
+ addr = __alloc_bootmem_node_nopanic(
+ NODE_DATA(hstate_next_node_to_alloc(h,
+ &node_states[N_HIGH_MEMORY])),
+ huge_page_size(h), huge_page_size(h), 0);
+
+ 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;
+ goto found;
+ }
+ nr_nodes--;
+ }
+ return 0;
+
+found:
+ BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
+ /* Put them into a private list first because mem_map is not up yet */
+ list_add(&m->list, &huge_boot_pages);
+ m->hstate = h;
+ return 1;
+}
+
+static void prep_compound_huge_page(struct page *page, int order)
+{
+ if (unlikely(order > (MAX_ORDER - 1)))
+ prep_compound_gigantic_page(page, order);
+ else
+ prep_compound_page(page, order);
+}
+
+/* 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) {
+ struct page *page = virt_to_page(m);
+ struct hstate *h = m->hstate;
+ __ClearPageReserved(page);
+ WARN_ON(page_count(page) != 1);
+ prep_compound_huge_page(page, h->order);
+ prep_new_huge_page(h, page, page_to_nid(page));
+ /*
+ * 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.
+ */
+ if (h->order > (MAX_ORDER - 1))
+ totalram_pages += 1 << h->order;
+ }
+}
+
+static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
+{
+ unsigned long i;
+
+ for (i = 0; i < h->max_huge_pages; ++i) {
+ if (h->order >= MAX_ORDER) {
+ if (!alloc_bootmem_huge_page(h))
+ break;
+ } else if (!alloc_fresh_huge_page(h,
+ &node_states[N_HIGH_MEMORY]))
+ break;
+ }
+ h->max_huge_pages = i;
+}
+
+static void __init hugetlb_init_hstates(void)
+{
+ struct hstate *h;
+
+ for_each_hstate(h) {
+ /* oversize hugepages were init'ed in early boot */
+ if (h->order < MAX_ORDER)
+ hugetlb_hstate_alloc_pages(h);
+ }
+}
+
+static char * __init memfmt(char *buf, unsigned long n)
+{
+ if (n >= (1UL << 30))
+ sprintf(buf, "%lu GB", n >> 30);
+ else if (n >= (1UL << 20))
+ sprintf(buf, "%lu MB", n >> 20);
+ else
+ sprintf(buf, "%lu KB", n >> 10);
+ return buf;
+}
+
+static void __init report_hugepages(void)
+{
+ struct hstate *h;
+
+ for_each_hstate(h) {
+ char buf[32];
+ printk(KERN_INFO "HugeTLB registered %s page size, "
+ "pre-allocated %ld pages\n",
+ memfmt(buf, huge_page_size(h)),
+ h->free_huge_pages);
+ }
+}
+
+#ifdef CONFIG_HIGHMEM
+static void try_to_free_low(struct hstate *h, unsigned long count,
+ nodemask_t *nodes_allowed)
+{
+ int i;
+
+ if (h->order >= MAX_ORDER)
+ return;
+
+ for_each_node_mask(i, *nodes_allowed) {
+ struct page *page, *next;
+ struct list_head *freel = &h->hugepage_freelists[i];
+ list_for_each_entry_safe(page, next, freel, lru) {
+ if (count >= h->nr_huge_pages)
+ return;
+ if (PageHighMem(page))
+ continue;
+ list_del(&page->lru);
+ update_and_free_page(h, page);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[page_to_nid(page)]--;
+ }
+ }
+}
+#else
+static inline void try_to_free_low(struct hstate *h, unsigned long count,
+ nodemask_t *nodes_allowed)
+{
+}
+#endif
+
+/*
+ * 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.
+ */
+static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
+ int delta)
+{
+ int start_nid, next_nid;
+ int ret = 0;
+
+ VM_BUG_ON(delta != -1 && delta != 1);
+
+ if (delta < 0)
+ start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
+ else
+ start_nid = hstate_next_node_to_free(h, nodes_allowed);
+ next_nid = start_nid;
+
+ do {
+ int nid = next_nid;
+ if (delta < 0) {
+ /*
+ * To shrink on this node, there must be a surplus page
+ */
+ if (!h->surplus_huge_pages_node[nid]) {
+ next_nid = hstate_next_node_to_alloc(h,
+ nodes_allowed);
+ continue;
+ }
+ }
+ if (delta > 0) {
+ /*
+ * Surplus cannot exceed the total number of pages
+ */
+ if (h->surplus_huge_pages_node[nid] >=
+ h->nr_huge_pages_node[nid]) {
+ next_nid = hstate_next_node_to_free(h,
+ nodes_allowed);
+ continue;
+ }
+ }
+
+ h->surplus_huge_pages += delta;
+ h->surplus_huge_pages_node[nid] += delta;
+ ret = 1;
+ break;
+ } while (next_nid != start_nid);
+
+ return ret;
+}
+
+#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
+static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
+ nodemask_t *nodes_allowed)
+{
+ unsigned long min_count, ret;
+
+ if (h->order >= MAX_ORDER)
+ return h->max_huge_pages;
+
+ /*
+ * Increase the pool size
+ * First take pages out of surplus state. Then make up the
+ * remaining difference by allocating fresh huge pages.
+ *
+ * We might race with alloc_buddy_huge_page() here and be unable
+ * 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.
+ */
+ spin_lock(&hugetlb_lock);
+ while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
+ if (!adjust_pool_surplus(h, nodes_allowed, -1))
+ break;
+ }
+
+ while (count > persistent_huge_pages(h)) {
+ /*
+ * 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);
+ ret = alloc_fresh_huge_page(h, nodes_allowed);
+ spin_lock(&hugetlb_lock);
+ if (!ret)
+ goto out;
+
+ /* Bail for signals. Probably ctrl-c from user */
+ if (signal_pending(current))
+ goto out;
+ }
+
+ /*
+ * 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.
+ *
+ * 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
+ * alloc_buddy_huge_page() is checking the global counter,
+ * 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.
+ */
+ min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
+ min_count = max(count, min_count);
+ try_to_free_low(h, min_count, nodes_allowed);
+ while (min_count < persistent_huge_pages(h)) {
+ if (!free_pool_huge_page(h, nodes_allowed, 0))
+ break;
+ }
+ while (count < persistent_huge_pages(h)) {
+ if (!adjust_pool_surplus(h, nodes_allowed, 1))
+ break;
+ }
+out:
+ ret = persistent_huge_pages(h);
+ spin_unlock(&hugetlb_lock);
+ return ret;
+}
+
+#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];
+
+static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
+
+static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
+{
+ int i;
+
+ for (i = 0; i < HUGE_MAX_HSTATE; i++)
+ if (hstate_kobjs[i] == kobj) {
+ if (nidp)
+ *nidp = NUMA_NO_NODE;
+ return &hstates[i];
+ }
+
+ return kobj_to_node_hstate(kobj, nidp);
+}
+
+static ssize_t nr_hugepages_show_common(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ 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);
+}
+
+static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
+ struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t len)
+{
+ int err;
+ int nid;
+ unsigned long count;
+ struct hstate *h;
+ NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
+
+ err = strict_strtoul(buf, 10, &count);
+ if (err)
+ goto out;
+
+ h = kobj_to_hstate(kobj, &nid);
+ if (h->order >= MAX_ORDER) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (nid == NUMA_NO_NODE) {
+ /*
+ * global hstate attribute
+ */
+ if (!(obey_mempolicy &&
+ init_nodemask_of_mempolicy(nodes_allowed))) {
+ NODEMASK_FREE(nodes_allowed);
+ nodes_allowed = &node_states[N_HIGH_MEMORY];
+ }
+ } else if (nodes_allowed) {
+ /*
+ * per node hstate attribute: adjust count to global,
+ * but restrict alloc/free to the specified node.
+ */
+ count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
+ init_nodemask_of_node(nodes_allowed, nid);
+ } else
+ nodes_allowed = &node_states[N_HIGH_MEMORY];
+
+ h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
+
+ if (nodes_allowed != &node_states[N_HIGH_MEMORY])
+ NODEMASK_FREE(nodes_allowed);
+
+ return len;
+out:
+ NODEMASK_FREE(nodes_allowed);
+ return err;
+}
+
+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)
+{
+ return nr_hugepages_store_common(false, kobj, attr, buf, len);
+}
+HSTATE_ATTR(nr_hugepages);
+
+#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)
+{
+ return nr_hugepages_store_common(true, kobj, attr, buf, len);
+}
+HSTATE_ATTR(nr_hugepages_mempolicy);
+#endif
+
+
+static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct hstate *h = kobj_to_hstate(kobj, NULL);
+ return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
+}
+
+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;
+ struct hstate *h = kobj_to_hstate(kobj, NULL);
+
+ if (h->order >= MAX_ORDER)
+ return -EINVAL;
+
+ err = strict_strtoul(buf, 10, &input);
+ if (err)
+ return err;
+
+ 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)
+{
+ 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);
+}
+HSTATE_ATTR_RO(free_hugepages);
+
+static ssize_t resv_hugepages_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ struct hstate *h = kobj_to_hstate(kobj, NULL);
+ 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)
+{
+ 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);
+}
+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,
+#ifdef CONFIG_NUMA
+ &nr_hugepages_mempolicy_attr.attr,
+#endif
+ NULL,
+};
+
+static struct attribute_group hstate_attr_group = {
+ .attrs = hstate_attrs,
+};
+
+static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
+ struct kobject **hstate_kobjs,
+ struct attribute_group *hstate_attr_group)
+{
+ int retval;
+ int hi = h - hstates;
+
+ hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
+ if (!hstate_kobjs[hi])
+ return -ENOMEM;
+
+ retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
+ if (retval)
+ kobject_put(hstate_kobjs[hi]);
+
+ 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) {
+ err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
+ hstate_kobjs, &hstate_attr_group);
+ if (err)
+ printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
+ h->name);
+ }
+}
+
+#ifdef CONFIG_NUMA
+
+/*
+ * node_hstate/s - associate per node hstate attributes, via their kobjects,
+ * with node sysdevs in node_devices[] using a parallel array. The array
+ * index of a node sysdev or _hstate == node id.
+ * This is here to avoid any static dependency of the node sysdev driver, in
+ * the base kernel, on the hugetlb module.
+ */
+struct node_hstate {
+ struct kobject *hugepages_kobj;
+ struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
+};
+struct node_hstate node_hstates[MAX_NUMNODES];
+
+/*
+ * A subset of global hstate attributes for node sysdevs
+ */
+static struct attribute *per_node_hstate_attrs[] = {
+ &nr_hugepages_attr.attr,
+ &free_hugepages_attr.attr,
+ &surplus_hugepages_attr.attr,
+ NULL,
+};
+
+static struct attribute_group per_node_hstate_attr_group = {
+ .attrs = per_node_hstate_attrs,
+};
+
+/*
+ * kobj_to_node_hstate - lookup global hstate for node sysdev hstate attr kobj.
+ * 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;
+}
+
+/*
+ * Unregister hstate attributes from a single node sysdev.
+ * No-op if no hstate attributes attached.
+ */
+void hugetlb_unregister_node(struct node *node)
+{
+ struct hstate *h;
+ struct node_hstate *nhs = &node_hstates[node->sysdev.id];
+
+ if (!nhs->hugepages_kobj)
+ return; /* no hstate attributes */
+
+ for_each_hstate(h)
+ if (nhs->hstate_kobjs[h - hstates]) {
+ kobject_put(nhs->hstate_kobjs[h - hstates]);
+ nhs->hstate_kobjs[h - hstates] = NULL;
+ }
+
+ kobject_put(nhs->hugepages_kobj);
+ nhs->hugepages_kobj = NULL;
+}
+
+/*
+ * hugetlb module exit: unregister hstate attributes from node sysdevs
+ * that have them.
+ */
+static void hugetlb_unregister_all_nodes(void)
+{
+ int nid;
+
+ /*
+ * disable node sysdev registrations.
+ */
+ register_hugetlbfs_with_node(NULL, NULL);
+
+ /*
+ * remove hstate attributes from any nodes that have them.
+ */
+ for (nid = 0; nid < nr_node_ids; nid++)
+ hugetlb_unregister_node(&node_devices[nid]);
+}
+
+/*
+ * Register hstate attributes for a single node sysdev.
+ * No-op if attributes already registered.
+ */
+void hugetlb_register_node(struct node *node)
+{
+ struct hstate *h;
+ struct node_hstate *nhs = &node_hstates[node->sysdev.id];
+ int err;
+
+ if (nhs->hugepages_kobj)
+ return; /* already allocated */
+
+ nhs->hugepages_kobj = kobject_create_and_add("hugepages",
+ &node->sysdev.kobj);
+ 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) {
+ printk(KERN_ERR "Hugetlb: Unable to add hstate %s"
+ " for node %d\n",
+ h->name, node->sysdev.id);
+ hugetlb_unregister_node(node);
+ break;
+ }
+ }
+}
+
+/*
+ * hugetlb init time: register hstate attributes for all registered node
+ * sysdevs of nodes that have memory. All on-line nodes should have
+ * registered their associated sysdev by this time.
+ */
+static void hugetlb_register_all_nodes(void)
+{
+ int nid;
+
+ for_each_node_state(nid, N_HIGH_MEMORY) {
+ struct node *node = &node_devices[nid];
+ if (node->sysdev.id == nid)
+ hugetlb_register_node(node);
+ }
+
+ /*
+ * Let the node sysdev driver know we're here so it can
+ * [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_unregister_all_nodes(void) { }
+
+static void hugetlb_register_all_nodes(void) { }
+
+#endif
+
+static void __exit hugetlb_exit(void)
+{
+ struct hstate *h;
+
+ hugetlb_unregister_all_nodes();
+
+ for_each_hstate(h) {
+ kobject_put(hstate_kobjs[h - hstates]);
+ }
+
+ kobject_put(hugepages_kobj);
+}
+module_exit(hugetlb_exit);
+
+static int __init hugetlb_init(void)
+{
+ /* Some platform decide whether they support huge pages at boot
+ * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
+ * there is no such support
+ */
+ if (HPAGE_SHIFT == 0)
+ return 0;
+
+ if (!size_to_hstate(default_hstate_size)) {
+ default_hstate_size = HPAGE_SIZE;
+ if (!size_to_hstate(default_hstate_size))
+ hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
+ }
+ default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
+ if (default_hstate_max_huge_pages)
+ default_hstate.max_huge_pages = default_hstate_max_huge_pages;
+
+ hugetlb_init_hstates();
+
+ gather_bootmem_prealloc();
+
+ report_hugepages();
+
+ hugetlb_sysfs_init();
+
+ hugetlb_register_all_nodes();
+
+ return 0;
+}
+module_init(hugetlb_init);
+
+/* Should be called on processing a hugepagesz=... option */
+void __init hugetlb_add_hstate(unsigned order)
+{
+ struct hstate *h;
+ unsigned long i;
+
+ if (size_to_hstate(PAGE_SIZE << order)) {
+ printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
+ return;
+ }
+ BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
+ BUG_ON(order == 0);
+ h = &hstates[max_hstate++];
+ h->order = order;
+ h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
+ h->nr_huge_pages = 0;
+ h->free_huge_pages = 0;
+ for (i = 0; i < MAX_NUMNODES; ++i)
+ INIT_LIST_HEAD(&h->hugepage_freelists[i]);
+ h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
+ h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
+ snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
+ huge_page_size(h)/1024);
+
+ parsed_hstate = h;
+}
+
+static int __init hugetlb_nrpages_setup(char *s)
+{
+ unsigned long *mhp;
+ static unsigned long *last_mhp;
+
+ /*
+ * !max_hstate means we haven't parsed a hugepagesz= parameter yet,
+ * so this hugepages= parameter goes to the "default hstate".
+ */
+ if (!max_hstate)
+ mhp = &default_hstate_max_huge_pages;
+ else
+ mhp = &parsed_hstate->max_huge_pages;
+
+ if (mhp == last_mhp) {
+ printk(KERN_WARNING "hugepages= specified twice without "
+ "interleaving hugepagesz=, ignoring\n");
+ return 1;
+ }
+
+ if (sscanf(s, "%lu", mhp) <= 0)
+ *mhp = 0;
+
+ /*
+ * 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.
+ */
+ if (max_hstate && parsed_hstate->order >= MAX_ORDER)
+ hugetlb_hstate_alloc_pages(parsed_hstate);
+
+ last_mhp = mhp;
+
+ return 1;
+}
+__setup("hugepages=", hugetlb_nrpages_setup);
+
+static int __init hugetlb_default_setup(char *s)
+{
+ default_hstate_size = memparse(s, &s);
+ return 1;
+}
+__setup("default_hugepagesz=", hugetlb_default_setup);
+
+static unsigned int cpuset_mems_nr(unsigned int *array)
+{
+ int node;
+ unsigned int nr = 0;
+
+ for_each_node_mask(node, cpuset_current_mems_allowed)
+ nr += array[node];
+
+ return nr;
+}
+
+#ifdef CONFIG_SYSCTL
+static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
+ struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ struct hstate *h = &default_hstate;
+ unsigned long tmp;
+ int ret;
+
+ tmp = h->max_huge_pages;
+
+ if (write && h->order >= MAX_ORDER)
+ return -EINVAL;
+
+ table->data = &tmp;
+ table->maxlen = sizeof(unsigned long);
+ ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
+ if (ret)
+ goto out;
+
+ if (write) {
+ NODEMASK_ALLOC(nodemask_t, nodes_allowed,
+ GFP_KERNEL | __GFP_NORETRY);
+ if (!(obey_mempolicy &&
+ init_nodemask_of_mempolicy(nodes_allowed))) {
+ NODEMASK_FREE(nodes_allowed);
+ nodes_allowed = &node_states[N_HIGH_MEMORY];
+ }
+ h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
+
+ if (nodes_allowed != &node_states[N_HIGH_MEMORY])
+ NODEMASK_FREE(nodes_allowed);
+ }
+out:
+ return ret;
+}
+
+int hugetlb_sysctl_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+
+ return hugetlb_sysctl_handler_common(false, table, write,
+ buffer, length, ppos);
+}
+
+#ifdef CONFIG_NUMA
+int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ return hugetlb_sysctl_handler_common(true, table, write,
+ buffer, length, ppos);
+}
+#endif /* CONFIG_NUMA */
+
+int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
+ void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ proc_dointvec(table, write, buffer, length, ppos);
+ if (hugepages_treat_as_movable)
+ htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
+ else
+ htlb_alloc_mask = GFP_HIGHUSER;
+ return 0;
+}
+
+int hugetlb_overcommit_handler(struct ctl_table *table, int write,
+ void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ struct hstate *h = &default_hstate;
+ unsigned long tmp;
+ int ret;
+
+ tmp = h->nr_overcommit_huge_pages;
+
+ if (write && h->order >= MAX_ORDER)
+ return -EINVAL;
+
+ table->data = &tmp;
+ table->maxlen = sizeof(unsigned long);
+ ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
+ if (ret)
+ goto out;
+
+ if (write) {
+ spin_lock(&hugetlb_lock);
+ h->nr_overcommit_huge_pages = tmp;
+ spin_unlock(&hugetlb_lock);
+ }
+out:
+ return ret;
+}
+
+#endif /* CONFIG_SYSCTL */
+
+void hugetlb_report_meminfo(struct seq_file *m)
+{
+ struct hstate *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",
+ h->nr_huge_pages,
+ h->free_huge_pages,
+ h->resv_huge_pages,
+ h->surplus_huge_pages,
+ 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
+}
+
+int hugetlb_report_node_meminfo(int nid, char *buf)
+{
+ struct hstate *h = &default_hstate;
+ return sprintf(buf,
+ "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]);
+}
+
+/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
+unsigned long hugetlb_total_pages(void)
+{
+ struct hstate *h = &default_hstate;
+ return h->nr_huge_pages * pages_per_huge_page(h);
+}
+
+static int hugetlb_acct_memory(struct hstate *h, long delta)
+{
+ int ret = -ENOMEM;
+
+ spin_lock(&hugetlb_lock);
+ /*
+ * When cpuset is configured, it breaks the strict hugetlb page
+ * reservation as the accounting is done on a global variable. Such
+ * reservation is completely rubbish in the presence of cpuset because
+ * the reservation is not checked against page availability for the
+ * current cpuset. Application can still potentially OOM'ed by kernel
+ * with lack of free htlb page in cpuset that the task is in.
+ * Attempt to enforce strict accounting with cpuset is almost
+ * impossible (or too ugly) because cpuset is too fluid that
+ * task or memory node can be dynamically moved between cpusets.
+ *
+ * The change of semantics for shared hugetlb mapping with cpuset is
+ * undesirable. However, in order to preserve some of the semantics,
+ * we fall back to check against current free page availability as
+ * a best attempt and hopefully to minimize the impact of changing
+ * semantics that cpuset has.
+ */
+ if (delta > 0) {
+ if (gather_surplus_pages(h, delta) < 0)
+ goto out;
+
+ if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
+ return_unused_surplus_pages(h, delta);
+ goto out;
+ }
+ }
+
+ ret = 0;
+ if (delta < 0)
+ return_unused_surplus_pages(h, (unsigned long) -delta);
+
+out:
+ spin_unlock(&hugetlb_lock);
+ return ret;
+}
+
+static void hugetlb_vm_op_open(struct vm_area_struct *vma)
+{
+ struct resv_map *reservations = vma_resv_map(vma);
+
+ /*
+ * 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
+ * has a reference to the reservation map it cannot disappear until
+ * after this open call completes. It is therefore safe to take a
+ * new reference here without additional locking.
+ */
+ if (reservations)
+ kref_get(&reservations->refs);
+}
+
+static void resv_map_put(struct vm_area_struct *vma)
+{
+ struct resv_map *reservations = vma_resv_map(vma);
+
+ if (!reservations)
+ return;
+ kref_put(&reservations->refs, resv_map_release);
+}
+
+static void hugetlb_vm_op_close(struct vm_area_struct *vma)
+{
+ struct hstate *h = hstate_vma(vma);
+ struct resv_map *reservations = vma_resv_map(vma);
+ unsigned long reserve;
+ unsigned long start;
+ unsigned long end;
+
+ if (reservations) {
+ start = vma_hugecache_offset(h, vma, vma->vm_start);
+ end = vma_hugecache_offset(h, vma, vma->vm_end);
+
+ reserve = (end - start) -
+ region_count(&reservations->regions, start, end);
+
+ resv_map_put(vma);
+
+ if (reserve) {
+ hugetlb_acct_memory(h, -reserve);
+ hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
+ }
+ }
+}
+
+/*
+ * 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.
+ */
+static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ BUG();
+ return 0;
+}
+
+const struct vm_operations_struct hugetlb_vm_ops = {
+ .fault = hugetlb_vm_op_fault,
+ .open = hugetlb_vm_op_open,
+ .close = hugetlb_vm_op_close,
+};
+
+static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
+ int writable)
+{
+ pte_t entry;
+
+ if (writable) {
+ entry =
+ pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
+ } else {
+ entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
+ }
+ entry = pte_mkyoung(entry);
+ entry = pte_mkhuge(entry);
+
+ return entry;
+}
+
+static void set_huge_ptep_writable(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep)
+{
+ pte_t entry;
+
+ entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
+ if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) {
+ update_mmu_cache(vma, address, ptep);
+ }
+}
+
+
+int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
+ struct vm_area_struct *vma)
+{
+ pte_t *src_pte, *dst_pte, entry;
+ struct page *ptepage;
+ unsigned long addr;
+ int cow;
+ struct hstate *h = hstate_vma(vma);
+ unsigned long sz = huge_page_size(h);
+
+ cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
+
+ for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
+ src_pte = huge_pte_offset(src, addr);
+ if (!src_pte)
+ continue;
+ dst_pte = huge_pte_alloc(dst, addr, sz);
+ if (!dst_pte)
+ goto nomem;
+
+ /* If the pagetables are shared don't copy or take references */
+ if (dst_pte == src_pte)
+ continue;
+
+ spin_lock(&dst->page_table_lock);
+ spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
+ if (!huge_pte_none(huge_ptep_get(src_pte))) {
+ if (cow)
+ huge_ptep_set_wrprotect(src, addr, src_pte);
+ entry = huge_ptep_get(src_pte);
+ ptepage = pte_page(entry);
+ get_page(ptepage);
+ page_dup_rmap(ptepage);
+ set_huge_pte_at(dst, addr, dst_pte, entry);
+ }
+ spin_unlock(&src->page_table_lock);
+ spin_unlock(&dst->page_table_lock);
+ }
+ return 0;
+
+nomem:
+ return -ENOMEM;
+}
+
+static int is_hugetlb_entry_migration(pte_t pte)
+{
+ swp_entry_t swp;
+
+ if (huge_pte_none(pte) || pte_present(pte))
+ return 0;
+ swp = pte_to_swp_entry(pte);
+ if (non_swap_entry(swp) && is_migration_entry(swp)) {
+ return 1;
+ } else
+ return 0;
+}
+
+static int is_hugetlb_entry_hwpoisoned(pte_t pte)
+{
+ swp_entry_t swp;
+
+ if (huge_pte_none(pte) || pte_present(pte))
+ return 0;
+ swp = pte_to_swp_entry(pte);
+ if (non_swap_entry(swp) && is_hwpoison_entry(swp)) {
+ return 1;
+ } else
+ return 0;
+}
+
+void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, struct page *ref_page)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long address;
+ pte_t *ptep;
+ pte_t pte;
+ struct page *page;
+ struct page *tmp;
+ struct hstate *h = hstate_vma(vma);
+ unsigned long sz = huge_page_size(h);
+
+ /*
+ * A page gathering list, protected by per file i_mmap_mutex. The
+ * lock is used to avoid list corruption from multiple unmapping
+ * of the same page since we are using page->lru.
+ */
+ LIST_HEAD(page_list);
+
+ WARN_ON(!is_vm_hugetlb_page(vma));
+ BUG_ON(start & ~huge_page_mask(h));
+ BUG_ON(end & ~huge_page_mask(h));
+
+ mmu_notifier_invalidate_range_start(mm, start, end);
+ spin_lock(&mm->page_table_lock);
+ for (address = start; address < end; address += sz) {
+ ptep = huge_pte_offset(mm, address);
+ if (!ptep)
+ continue;
+
+ if (huge_pmd_unshare(mm, &address, ptep))
+ continue;
+
+ /*
+ * 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) {
+ pte = huge_ptep_get(ptep);
+ if (huge_pte_none(pte))
+ continue;
+ page = pte_page(pte);
+ if (page != ref_page)
+ continue;
+
+ /*
+ * 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);
+ }
+
+ pte = huge_ptep_get_and_clear(mm, address, ptep);
+ if (huge_pte_none(pte))
+ continue;
+
+ /*
+ * HWPoisoned hugepage is already unmapped and dropped reference
+ */
+ if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
+ continue;
+
+ page = pte_page(pte);
+ if (pte_dirty(pte))
+ set_page_dirty(page);
+ list_add(&page->lru, &page_list);
+ }
+ spin_unlock(&mm->page_table_lock);
+ flush_tlb_range(vma, start, end);
+ mmu_notifier_invalidate_range_end(mm, start, end);
+ list_for_each_entry_safe(page, tmp, &page_list, lru) {
+ page_remove_rmap(page);
+ list_del(&page->lru);
+ put_page(page);
+ }
+}
+
+void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, struct page *ref_page)
+{
+ mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ __unmap_hugepage_range(vma, start, end, ref_page);
+ mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
+}
+
+/*
+ * 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.
+ */
+static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct page *page, unsigned long address)
+{
+ struct hstate *h = hstate_vma(vma);
+ struct vm_area_struct *iter_vma;
+ struct address_space *mapping;
+ struct prio_tree_iter iter;
+ pgoff_t pgoff;
+
+ /*
+ * vm_pgoff is in PAGE_SIZE units, hence the different calculation
+ * from page cache lookup which is in HPAGE_SIZE units.
+ */
+ address = address & huge_page_mask(h);
+ pgoff = ((address - vma->vm_start) >> PAGE_SHIFT)
+ + (vma->vm_pgoff >> PAGE_SHIFT);
+ mapping = (struct address_space *)page_private(page);
+
+ /*
+ * 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
+ */
+ mutex_lock(&mapping->i_mmap_mutex);
+ vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
+ /* Do not unmap the current VMA */
+ if (iter_vma == vma)
+ continue;
+
+ /*
+ * 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))
+ __unmap_hugepage_range(iter_vma,
+ address, address + huge_page_size(h),
+ page);
+ }
+ mutex_unlock(&mapping->i_mmap_mutex);
+
+ return 1;
+}
+
+/*
+ * Hugetlb_cow() should be called with page lock of the original hugepage held.
+ */
+static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep, pte_t pte,
+ struct page *pagecache_page)
+{
+ struct hstate *h = hstate_vma(vma);
+ struct page *old_page, *new_page;
+ int avoidcopy;
+ int outside_reserve = 0;
+
+ old_page = pte_page(pte);
+
+retry_avoidcopy:
+ /* If no-one else is actually using this page, avoid the copy
+ * and just make the page writable */
+ avoidcopy = (page_mapcount(old_page) == 1);
+ if (avoidcopy) {
+ if (PageAnon(old_page))
+ page_move_anon_rmap(old_page, vma, address);
+ set_huge_ptep_writable(vma, address, ptep);
+ return 0;
+ }
+
+ /*
+ * 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.
+ */
+ if (!(vma->vm_flags & VM_MAYSHARE) &&
+ is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
+ old_page != pagecache_page)
+ outside_reserve = 1;
+
+ page_cache_get(old_page);
+
+ /* Drop page_table_lock as buddy allocator may be called */
+ spin_unlock(&mm->page_table_lock);
+ new_page = alloc_huge_page(vma, address, outside_reserve);
+
+ if (IS_ERR(new_page)) {
+ page_cache_release(old_page);
+
+ /*
+ * 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) {
+ BUG_ON(huge_pte_none(pte));
+ if (unmap_ref_private(mm, vma, old_page, address)) {
+ BUG_ON(huge_pte_none(pte));
+ spin_lock(&mm->page_table_lock);
+ goto retry_avoidcopy;
+ }
+ WARN_ON_ONCE(1);
+ }
+
+ /* Caller expects lock to be held */
+ spin_lock(&mm->page_table_lock);
+ return -PTR_ERR(new_page);
+ }
+
+ /*
+ * When the original hugepage is shared one, it does not have
+ * anon_vma prepared.
+ */
+ if (unlikely(anon_vma_prepare(vma))) {
+ page_cache_release(new_page);
+ page_cache_release(old_page);
+ /* Caller expects lock to be held */
+ spin_lock(&mm->page_table_lock);
+ return VM_FAULT_OOM;
+ }
+
+ copy_user_huge_page(new_page, old_page, address, vma,
+ pages_per_huge_page(h));
+ __SetPageUptodate(new_page);
+
+ /*
+ * Retake the page_table_lock to check for racing updates
+ * before the page tables are altered
+ */
+ spin_lock(&mm->page_table_lock);
+ ptep = huge_pte_offset(mm, address & huge_page_mask(h));
+ if (likely(pte_same(huge_ptep_get(ptep), pte))) {
+ /* Break COW */
+ mmu_notifier_invalidate_range_start(mm,
+ address & huge_page_mask(h),
+ (address & huge_page_mask(h)) + huge_page_size(h));
+ huge_ptep_clear_flush(vma, address, ptep);
+ set_huge_pte_at(mm, address, ptep,
+ make_huge_pte(vma, new_page, 1));
+ page_remove_rmap(old_page);
+ hugepage_add_new_anon_rmap(new_page, vma, address);
+ /* Make the old page be freed below */
+ new_page = old_page;
+ mmu_notifier_invalidate_range_end(mm,
+ address & huge_page_mask(h),
+ (address & huge_page_mask(h)) + huge_page_size(h));
+ }
+ page_cache_release(new_page);
+ page_cache_release(old_page);
+ return 0;
+}
+
+/* Return the pagecache page at a given address within a VMA */
+static struct page *hugetlbfs_pagecache_page(struct hstate *h,
+ struct vm_area_struct *vma, unsigned long address)
+{
+ struct address_space *mapping;
+ pgoff_t idx;
+
+ mapping = vma->vm_file->f_mapping;
+ idx = vma_hugecache_offset(h, vma, address);
+
+ return find_lock_page(mapping, idx);
+}
+
+/*
+ * 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,
+ 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;
+}
+
+static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep, unsigned int flags)
+{
+ struct hstate *h = hstate_vma(vma);
+ int ret = VM_FAULT_SIGBUS;
+ pgoff_t idx;
+ unsigned long size;
+ struct page *page;
+ struct address_space *mapping;
+ pte_t new_pte;
+
+ /*
+ * Currently, we are forced to kill the process in the event the
+ * original mapper has unmapped pages from the child due to a failed
+ * COW. Warn that such a situation has occurred as it may not be obvious
+ */
+ if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
+ printk(KERN_WARNING
+ "PID %d killed due to inadequate hugepage pool\n",
+ current->pid);
+ return ret;
+ }
+
+ mapping = vma->vm_file->f_mapping;
+ idx = vma_hugecache_offset(h, vma, address);
+
+ /*
+ * Use page lock to guard against racing truncation
+ * before we get page_table_lock.
+ */
+retry:
+ page = find_lock_page(mapping, idx);
+ if (!page) {
+ size = i_size_read(mapping->host) >> huge_page_shift(h);
+ if (idx >= size)
+ goto out;
+ page = alloc_huge_page(vma, address, 0);
+ if (IS_ERR(page)) {
+ ret = -PTR_ERR(page);
+ goto out;
+ }
+ clear_huge_page(page, address, pages_per_huge_page(h));
+ __SetPageUptodate(page);
+
+ if (vma->vm_flags & VM_MAYSHARE) {
+ int err;
+ struct inode *inode = mapping->host;
+
+ err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
+ if (err) {
+ put_page(page);
+ if (err == -EEXIST)
+ goto retry;
+ goto out;
+ }
+
+ spin_lock(&inode->i_lock);
+ inode->i_blocks += blocks_per_huge_page(h);
+ spin_unlock(&inode->i_lock);
+ page_dup_rmap(page);
+ } else {
+ lock_page(page);
+ if (unlikely(anon_vma_prepare(vma))) {
+ ret = VM_FAULT_OOM;
+ goto backout_unlocked;
+ }
+ hugepage_add_new_anon_rmap(page, vma, address);
+ }
+ } else {
+ /*
+ * 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))) {
+ ret = VM_FAULT_HWPOISON |
+ VM_FAULT_SET_HINDEX(h - hstates);
+ goto backout_unlocked;
+ }
+ page_dup_rmap(page);
+ }
+
+ /*
+ * 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.
+ */
+ if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
+ if (vma_needs_reservation(h, vma, address) < 0) {
+ ret = VM_FAULT_OOM;
+ goto backout_unlocked;
+ }
+
+ spin_lock(&mm->page_table_lock);
+ size = i_size_read(mapping->host) >> huge_page_shift(h);
+ if (idx >= size)
+ goto backout;
+
+ ret = 0;
+ if (!huge_pte_none(huge_ptep_get(ptep)))
+ goto backout;
+
+ new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
+ && (vma->vm_flags & VM_SHARED)));
+ set_huge_pte_at(mm, address, ptep, new_pte);
+
+ if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
+ /* Optimization, do the COW without a second fault */
+ ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
+ }
+
+ spin_unlock(&mm->page_table_lock);
+ unlock_page(page);
+out:
+ return ret;
+
+backout:
+ spin_unlock(&mm->page_table_lock);
+backout_unlocked:
+ unlock_page(page);
+ put_page(page);
+ goto out;
+}
+
+int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, unsigned int flags)
+{
+ pte_t *ptep;
+ pte_t entry;
+ int ret;
+ struct page *page = NULL;
+ struct page *pagecache_page = NULL;
+ static DEFINE_MUTEX(hugetlb_instantiation_mutex);
+ struct hstate *h = hstate_vma(vma);
+
+ ptep = huge_pte_offset(mm, address);
+ if (ptep) {
+ entry = huge_ptep_get(ptep);
+ if (unlikely(is_hugetlb_entry_migration(entry))) {
+ migration_entry_wait(mm, (pmd_t *)ptep, address);
+ return 0;
+ } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
+ return VM_FAULT_HWPOISON_LARGE |
+ VM_FAULT_SET_HINDEX(h - hstates);
+ }
+
+ ptep = huge_pte_alloc(mm, address, huge_page_size(h));
+ if (!ptep)
+ return VM_FAULT_OOM;
+
+ /*
+ * 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.
+ */
+ mutex_lock(&hugetlb_instantiation_mutex);
+ entry = huge_ptep_get(ptep);
+ if (huge_pte_none(entry)) {
+ ret = hugetlb_no_page(mm, vma, address, ptep, flags);
+ goto out_mutex;
+ }
+
+ ret = 0;
+
+ /*
+ * 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.
+ */
+ if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
+ if (vma_needs_reservation(h, vma, address) < 0) {
+ ret = VM_FAULT_OOM;
+ goto out_mutex;
+ }
+
+ if (!(vma->vm_flags & VM_MAYSHARE))
+ pagecache_page = hugetlbfs_pagecache_page(h,
+ vma, address);
+ }
+
+ /*
+ * 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.
+ * Note that locking order is always pagecache_page -> page,
+ * so no worry about deadlock.
+ */
+ page = pte_page(entry);
+ get_page(page);
+ if (page != pagecache_page)
+ lock_page(page);
+
+ spin_lock(&mm->page_table_lock);
+ /* Check for a racing update before calling hugetlb_cow */
+ if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
+ goto out_page_table_lock;
+
+
+ if (flags & FAULT_FLAG_WRITE) {
+ if (!pte_write(entry)) {
+ ret = hugetlb_cow(mm, vma, address, ptep, entry,
+ pagecache_page);
+ goto out_page_table_lock;
+ }
+ entry = pte_mkdirty(entry);
+ }
+ entry = pte_mkyoung(entry);
+ if (huge_ptep_set_access_flags(vma, address, ptep, entry,
+ flags & FAULT_FLAG_WRITE))
+ update_mmu_cache(vma, address, ptep);
+
+out_page_table_lock:
+ spin_unlock(&mm->page_table_lock);
+
+ if (pagecache_page) {
+ unlock_page(pagecache_page);
+ put_page(pagecache_page);
+ }
+ if (page != pagecache_page)
+ unlock_page(page);
+ put_page(page);
+
+out_mutex:
+ mutex_unlock(&hugetlb_instantiation_mutex);
+
+ return ret;
+}
+
+/* Can be overriden by architectures */
+__attribute__((weak)) struct page *
+follow_huge_pud(struct mm_struct *mm, unsigned long address,
+ pud_t *pud, int write)
+{
+ BUG();
+ return NULL;
+}
+
+int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct page **pages, struct vm_area_struct **vmas,
+ unsigned long *position, int *length, int i,
+ unsigned int flags)
+{
+ unsigned long pfn_offset;
+ unsigned long vaddr = *position;
+ int remainder = *length;
+ struct hstate *h = hstate_vma(vma);
+
+ spin_lock(&mm->page_table_lock);
+ while (vaddr < vma->vm_end && remainder) {
+ pte_t *pte;
+ int absent;
+ struct page *page;
+
+ /*
+ * Some archs (sparc64, sh*) have multiple pte_ts to
+ * each hugepage. We have to make sure we get the
+ * first, for the page indexing below to work.
+ */
+ pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
+ absent = !pte || huge_pte_none(huge_ptep_get(pte));
+
+ /*
+ * When coredumping, it suits get_dump_page if we just return
+ * 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.
+ */
+ if (absent && (flags & FOLL_DUMP) &&
+ !hugetlbfs_pagecache_present(h, vma, vaddr)) {
+ remainder = 0;
+ break;
+ }
+
+ if (absent ||
+ ((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
+ int ret;
+
+ spin_unlock(&mm->page_table_lock);
+ ret = hugetlb_fault(mm, vma, vaddr,
+ (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
+ spin_lock(&mm->page_table_lock);
+ if (!(ret & VM_FAULT_ERROR))
+ continue;
+
+ remainder = 0;
+ break;
+ }
+
+ pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
+ page = pte_page(huge_ptep_get(pte));
+same_page:
+ if (pages) {
+ pages[i] = mem_map_offset(page, pfn_offset);
+ get_page(pages[i]);
+ }
+
+ if (vmas)
+ vmas[i] = vma;
+
+ vaddr += PAGE_SIZE;
+ ++pfn_offset;
+ --remainder;
+ ++i;
+ if (vaddr < vma->vm_end && remainder &&
+ pfn_offset < pages_per_huge_page(h)) {
+ /*
+ * We use pfn_offset to avoid touching the pageframes
+ * of this compound page.
+ */
+ goto same_page;
+ }
+ }
+ spin_unlock(&mm->page_table_lock);
+ *length = remainder;
+ *position = vaddr;
+
+ return i ? i : -EFAULT;
+}
+
+void hugetlb_change_protection(struct vm_area_struct *vma,
+ 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;
+ struct hstate *h = hstate_vma(vma);
+
+ BUG_ON(address >= end);
+ flush_cache_range(vma, address, end);
+
+ mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ spin_lock(&mm->page_table_lock);
+ for (; address < end; address += huge_page_size(h)) {
+ ptep = huge_pte_offset(mm, address);
+ if (!ptep)
+ continue;
+ if (huge_pmd_unshare(mm, &address, ptep))
+ continue;
+ if (!huge_pte_none(huge_ptep_get(ptep))) {
+ pte = huge_ptep_get_and_clear(mm, address, ptep);
+ pte = pte_mkhuge(pte_modify(pte, newprot));
+ set_huge_pte_at(mm, address, ptep, pte);
+ }
+ }
+ spin_unlock(&mm->page_table_lock);
+ mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
+
+ flush_tlb_range(vma, start, end);
+}
+
+int hugetlb_reserve_pages(struct inode *inode,
+ long from, long to,
+ struct vm_area_struct *vma,
+ vm_flags_t vm_flags)
+{
+ long ret, chg;
+ struct hstate *h = hstate_inode(inode);
+
+ /*
+ * Only apply hugepage reservation if asked. At fault time, an
+ * attempt will be made for VM_NORESERVE to allocate a page
+ * and filesystem quota without using reserves
+ */
+ if (vm_flags & VM_NORESERVE)
+ return 0;
+
+ /*
+ * 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
+ */
+ if (!vma || vma->vm_flags & VM_MAYSHARE)
+ chg = region_chg(&inode->i_mapping->private_list, from, to);
+ else {
+ struct resv_map *resv_map = resv_map_alloc();
+ if (!resv_map)
+ return -ENOMEM;
+
+ chg = to - from;
+
+ set_vma_resv_map(vma, resv_map);
+ set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
+ }
+
+ if (chg < 0) {
+ ret = chg;
+ goto out_err;
+ }
+
+ /* There must be enough filesystem quota for the mapping */
+ if (hugetlb_get_quota(inode->i_mapping, chg)) {
+ ret = -ENOSPC;
+ goto out_err;
+ }
+
+ /*
+ * Check enough hugepages are available for the reservation.
+ * Hand back the quota if there are not
+ */
+ ret = hugetlb_acct_memory(h, chg);
+ if (ret < 0) {
+ hugetlb_put_quota(inode->i_mapping, chg);
+ goto out_err;
+ }
+
+ /*
+ * 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
+ */
+ if (!vma || vma->vm_flags & VM_MAYSHARE)
+ region_add(&inode->i_mapping->private_list, from, to);
+ return 0;
+out_err:
+ if (vma)
+ resv_map_put(vma);
+ return ret;
+}
+
+void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
+{
+ struct hstate *h = hstate_inode(inode);
+ long chg = region_truncate(&inode->i_mapping->private_list, offset);
+
+ spin_lock(&inode->i_lock);
+ inode->i_blocks -= (blocks_per_huge_page(h) * freed);
+ spin_unlock(&inode->i_lock);
+
+ hugetlb_put_quota(inode->i_mapping, (chg - freed));
+ hugetlb_acct_memory(h, -(chg - freed));
+}
+
+#ifdef CONFIG_MEMORY_FAILURE
+
+/* Should be called in hugetlb_lock */
+static int is_hugepage_on_freelist(struct page *hpage)
+{
+ struct page *page;
+ struct page *tmp;
+ struct hstate *h = page_hstate(hpage);
+ int nid = page_to_nid(hpage);
+
+ list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
+ if (page == hpage)
+ return 1;
+ return 0;
+}
+
+/*
+ * This function is called from memory failure code.
+ * Assume the caller holds page lock of the head page.
+ */
+int dequeue_hwpoisoned_huge_page(struct page *hpage)
+{
+ struct hstate *h = page_hstate(hpage);
+ int nid = page_to_nid(hpage);
+ int ret = -EBUSY;
+
+ spin_lock(&hugetlb_lock);
+ if (is_hugepage_on_freelist(hpage)) {
+ list_del(&hpage->lru);
+ set_page_refcounted(hpage);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[nid]--;
+ ret = 0;
+ }
+ spin_unlock(&hugetlb_lock);
+ return ret;
+}
+#endif