--- /dev/null
+/*
+ * Generic hugetlb support.
+ * (C) Nadia Yvette Chambers, 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/compiler.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 <linux/page-isolation.h>
+#include <linux/jhash.h>
+
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/tlb.h>
+
+#include <linux/io.h>
+#include <linux/hugetlb.h>
+#include <linux/hugetlb_cgroup.h>
+#include <linux/node.h>
+#include "internal.h"
+
+int hugepages_treat_as_movable;
+
+int hugetlb_max_hstate __read_mostly;
+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;
+
+/*
+ * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
+ * free_huge_pages, and surplus_huge_pages.
+ */
+DEFINE_SPINLOCK(hugetlb_lock);
+
+/*
+ * 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;
+static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp;
+
+/* Forward declaration */
+static int hugetlb_acct_memory(struct hstate *h, long delta);
+
+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
+ * remain, give up any reservations mased on minimum size and
+ * free the subpool */
+ if (free) {
+ if (spool->min_hpages != -1)
+ hugetlb_acct_memory(spool->hstate,
+ -spool->min_hpages);
+ kfree(spool);
+ }
+}
+
+struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
+ long min_hpages)
+{
+ struct hugepage_subpool *spool;
+
+ spool = kzalloc(sizeof(*spool), GFP_KERNEL);
+ if (!spool)
+ return NULL;
+
+ spin_lock_init(&spool->lock);
+ spool->count = 1;
+ 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;
+
+ 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);
+}
+
+/*
+ * Subpool accounting for allocating and reserving pages.
+ * Return -ENOMEM if there are not enough resources to satisfy the
+ * the request. Otherwise, return the number of pages by which the
+ * global pools must be adjusted (upward). The returned value may
+ * only be different than the passed value (delta) in the case where
+ * a subpool minimum size must be manitained.
+ */
+static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
+ long delta)
+{
+ long ret = delta;
+
+ if (!spool)
+ return ret;
+
+ spin_lock(&spool->lock);
+
+ 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;
+ }
+ }
+
+ if (spool->min_hpages != -1) { /* minimum size accounting */
+ 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);
+ return ret;
+}
+
+/*
+ * 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,
+ long delta)
+{
+ long ret = delta;
+
+ if (!spool)
+ return delta;
+
+ spin_lock(&spool->lock);
+
+ if (spool->max_hpages != -1) /* maximum size accounting */
+ spool->used_hpages -= delta;
+
+ if (spool->min_hpages != -1) { /* minimum size accounting */
+ 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.
+ */
+ unlock_or_release_subpool(spool);
+
+ return ret;
+}
+
+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)
+{
+ return subpool_inode(file_inode(vma->vm_file));
+}
+
+/*
+ * Region tracking -- allows tracking of reservations and instantiated pages
+ * across the pages in a mapping.
+ *
+ * The region data structures are embedded into a resv_map and
+ * protected by a resv_map's lock
+ */
+struct file_region {
+ struct list_head link;
+ long from;
+ long to;
+};
+
+static long region_add(struct resv_map *resv, long f, long t)
+{
+ struct list_head *head = &resv->regions;
+ struct file_region *rg, *nrg, *trg;
+
+ spin_lock(&resv->lock);
+ /* 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;
+ spin_unlock(&resv->lock);
+ return 0;
+}
+
+static long region_chg(struct resv_map *resv, long f, long t)
+{
+ struct list_head *head = &resv->regions;
+ struct file_region *rg, *nrg = NULL;
+ long chg = 0;
+
+retry:
+ spin_lock(&resv->lock);
+ /* 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) {
+ if (!nrg) {
+ spin_unlock(&resv->lock);
+ nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
+ if (!nrg)
+ return -ENOMEM;
+
+ nrg->from = f;
+ nrg->to = f;
+ INIT_LIST_HEAD(&nrg->link);
+ goto retry;
+ }
+
+ list_add(&nrg->link, rg->link.prev);
+ chg = t - f;
+ goto out_nrg;
+ }
+
+ /* 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)
+ goto out;
+
+ /* 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;
+ }
+
+out:
+ spin_unlock(&resv->lock);
+ /* We already know we raced and no longer need the new region */
+ kfree(nrg);
+ return chg;
+out_nrg:
+ spin_unlock(&resv->lock);
+ return chg;
+}
+
+static long region_truncate(struct resv_map *resv, long end)
+{
+ struct list_head *head = &resv->regions;
+ struct file_region *rg, *trg;
+ long chg = 0;
+
+ spin_lock(&resv->lock);
+ /* 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)
+ goto out;
+
+ /* 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);
+ }
+
+out:
+ spin_unlock(&resv->lock);
+ return chg;
+}
+
+static long region_count(struct resv_map *resv, long f, long t)
+{
+ struct list_head *head = &resv->regions;
+ struct file_region *rg;
+ long chg = 0;
+
+ spin_lock(&resv->lock);
+ /* Locate each segment we overlap with, and count that overlap. */
+ list_for_each_entry(rg, head, link) {
+ long seg_from;
+ long 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;
+ }
+ spin_unlock(&resv->lock);
+
+ 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 << huge_page_shift(hstate);
+}
+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 *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);
+ spin_lock_init(&resv_map->lock);
+ INIT_LIST_HEAD(&resv_map->regions);
+
+ return resv_map;
+}
+
+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, 0);
+ kfree(resv_map);
+}
+
+static inline struct resv_map *inode_resv_map(struct inode *inode)
+{
+ return inode->i_mapping->private_data;
+}
+
+static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
+{
+ VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
+ 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 {
+ return (struct resv_map *)(get_vma_private_data(vma) &
+ ~HPAGE_RESV_MASK);
+ }
+}
+
+static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
+{
+ VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
+ VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
+
+ 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_VMA(!is_vm_hugetlb_page(vma), vma);
+ VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
+
+ 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_VMA(!is_vm_hugetlb_page(vma), vma);
+
+ return (get_vma_private_data(vma) & flag) != 0;
+}
+
+/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
+void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
+{
+ VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), 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, long chg)
+{
+ 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)
+ return 1;
+ else
+ return 0;
+ }
+
+ /* Shared mappings always use reserves */
+ if (vma->vm_flags & VM_MAYSHARE)
+ return 1;
+
+ /*
+ * Only the process that called mmap() has reserves for
+ * private mappings.
+ */
+ if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
+ return 1;
+
+ return 0;
+}
+
+static void enqueue_huge_page(struct hstate *h, struct page *page)
+{
+ int nid = page_to_nid(page);
+ list_move(&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;
+
+ list_for_each_entry(page, &h->hugepage_freelists[nid], lru)
+ if (!is_migrate_isolate_page(page))
+ break;
+ /*
+ * if 'non-isolated free hugepage' not found on the list,
+ * the allocation fails.
+ */
+ if (&h->hugepage_freelists[nid] == &page->lru)
+ return NULL;
+ list_move(&page->lru, &h->hugepage_activelist);
+ set_page_refcounted(page);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[nid]--;
+ return page;
+}
+
+/* Movability of hugepages depends on migration support. */
+static inline gfp_t htlb_alloc_mask(struct hstate *h)
+{
+ if (hugepages_treat_as_movable || hugepage_migration_supported(h))
+ return GFP_HIGHUSER_MOVABLE;
+ else
+ return GFP_HIGHUSER;
+}
+
+static struct page *dequeue_huge_page_vma(struct hstate *h,
+ struct vm_area_struct *vma,
+ unsigned long address, int avoid_reserve,
+ long chg)
+{
+ struct page *page = NULL;
+ struct mempolicy *mpol;
+ nodemask_t *nodemask;
+ struct zonelist *zonelist;
+ struct zone *zone;
+ struct zoneref *z;
+ unsigned int cpuset_mems_cookie;
+
+ /*
+ * 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, chg) &&
+ 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;
+
+retry_cpuset:
+ cpuset_mems_cookie = read_mems_allowed_begin();
+ zonelist = huge_zonelist(vma, address,
+ htlb_alloc_mask(h), &mpol, &nodemask);
+
+ for_each_zone_zonelist_nodemask(zone, z, zonelist,
+ MAX_NR_ZONES - 1, nodemask) {
+ if (cpuset_zone_allowed(zone, htlb_alloc_mask(h))) {
+ page = dequeue_huge_page_node(h, zone_to_nid(zone));
+ if (page) {
+ if (avoid_reserve)
+ break;
+ if (!vma_has_reserves(vma, chg))
+ break;
+
+ SetPagePrivate(page);
+ h->resv_huge_pages--;
+ break;
+ }
+ }
+ }
+
+ mpol_cond_put(mpol);
+ if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie)))
+ goto retry_cpuset;
+ return page;
+
+err:
+ return NULL;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * 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--)
+
+#if defined(CONFIG_CMA) && defined(CONFIG_X86_64)
+static void destroy_compound_gigantic_page(struct page *page,
+ unsigned long order)
+{
+ int i;
+ int nr_pages = 1 << order;
+ struct page *p = page + 1;
+
+ for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
+ __ClearPageTail(p);
+ set_page_refcounted(p);
+ p->first_page = NULL;
+ }
+
+ set_compound_order(page, 0);
+ __ClearPageHead(page);
+}
+
+static void free_gigantic_page(struct page *page, unsigned order)
+{
+ free_contig_range(page_to_pfn(page), 1 << order);
+}
+
+static int __alloc_gigantic_page(unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long end_pfn = start_pfn + nr_pages;
+ return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
+}
+
+static bool pfn_range_valid_gigantic(unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long i, end_pfn = start_pfn + nr_pages;
+ struct page *page;
+
+ for (i = start_pfn; i < end_pfn; i++) {
+ if (!pfn_valid(i))
+ return false;
+
+ page = pfn_to_page(i);
+
+ if (PageReserved(page))
+ return false;
+
+ if (page_count(page) > 0)
+ return false;
+
+ if (PageHuge(page))
+ return false;
+ }
+
+ return true;
+}
+
+static bool zone_spans_last_pfn(const struct zone *zone,
+ unsigned long start_pfn, unsigned long nr_pages)
+{
+ unsigned long last_pfn = start_pfn + nr_pages - 1;
+ return zone_spans_pfn(zone, last_pfn);
+}
+
+static struct page *alloc_gigantic_page(int nid, unsigned order)
+{
+ unsigned long nr_pages = 1 << order;
+ unsigned long ret, pfn, flags;
+ struct zone *z;
+
+ z = NODE_DATA(nid)->node_zones;
+ for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) {
+ spin_lock_irqsave(&z->lock, flags);
+
+ pfn = ALIGN(z->zone_start_pfn, nr_pages);
+ while (zone_spans_last_pfn(z, pfn, nr_pages)) {
+ if (pfn_range_valid_gigantic(pfn, nr_pages)) {
+ /*
+ * We release the zone lock here because
+ * alloc_contig_range() will also lock the zone
+ * at some point. If there's an allocation
+ * spinning on this lock, it may win the race
+ * and cause alloc_contig_range() to fail...
+ */
+ spin_unlock_irqrestore(&z->lock, flags);
+ ret = __alloc_gigantic_page(pfn, nr_pages);
+ if (!ret)
+ return pfn_to_page(pfn);
+ spin_lock_irqsave(&z->lock, flags);
+ }
+ pfn += nr_pages;
+ }
+
+ spin_unlock_irqrestore(&z->lock, flags);
+ }
+
+ return NULL;
+}
+
+static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
+static void prep_compound_gigantic_page(struct page *page, unsigned long order);
+
+static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid)
+{
+ struct page *page;
+
+ page = alloc_gigantic_page(nid, huge_page_order(h));
+ if (page) {
+ prep_compound_gigantic_page(page, huge_page_order(h));
+ prep_new_huge_page(h, page, nid);
+ }
+
+ return page;
+}
+
+static int alloc_fresh_gigantic_page(struct hstate *h,
+ nodemask_t *nodes_allowed)
+{
+ struct page *page = NULL;
+ int nr_nodes, node;
+
+ for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
+ page = alloc_fresh_gigantic_page_node(h, node);
+ if (page)
+ return 1;
+ }
+
+ return 0;
+}
+
+static inline bool gigantic_page_supported(void) { return true; }
+#else
+static inline bool gigantic_page_supported(void) { return false; }
+static inline void free_gigantic_page(struct page *page, unsigned order) { }
+static inline void destroy_compound_gigantic_page(struct page *page,
+ unsigned long order) { }
+static inline int alloc_fresh_gigantic_page(struct hstate *h,
+ nodemask_t *nodes_allowed) { return 0; }
+#endif
+
+static void update_and_free_page(struct hstate *h, struct page *page)
+{
+ int i;
+
+ if (hstate_is_gigantic(h) && !gigantic_page_supported())
+ return;
+
+ 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_private |
+ 1 << PG_writeback);
+ }
+ VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
+ set_compound_page_dtor(page, NULL);
+ set_page_refcounted(page);
+ if (hstate_is_gigantic(h)) {
+ destroy_compound_gigantic_page(page, huge_page_order(h));
+ free_gigantic_page(page, huge_page_order(h));
+ } else {
+ 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;
+}
+
+/*
+ * 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]);
+}
+
+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 hugepage_subpool *spool =
+ (struct hugepage_subpool *)page_private(page);
+ bool restore_reserve;
+
+ set_page_private(page, 0);
+ page->mapping = NULL;
+ BUG_ON(page_count(page));
+ BUG_ON(page_mapcount(page));
+ restore_reserve = PagePrivate(page);
+ ClearPagePrivate(page);
+
+ /*
+ * 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;
+
+ spin_lock(&hugetlb_lock);
+ clear_page_huge_active(page);
+ hugetlb_cgroup_uncharge_page(hstate_index(h),
+ pages_per_huge_page(h), page);
+ if (restore_reserve)
+ h->resv_huge_pages++;
+
+ if (h->surplus_huge_pages_node[nid]) {
+ /* remove the page from active list */
+ list_del(&page->lru);
+ update_and_free_page(h, page);
+ h->surplus_huge_pages--;
+ h->surplus_huge_pages_node[nid]--;
+ } else {
+ arch_clear_hugepage_flags(page);
+ enqueue_huge_page(h, page);
+ }
+ spin_unlock(&hugetlb_lock);
+}
+
+static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
+{
+ INIT_LIST_HEAD(&page->lru);
+ set_compound_page_dtor(page, free_huge_page);
+ spin_lock(&hugetlb_lock);
+ set_hugetlb_cgroup(page, NULL);
+ 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);
+ __ClearPageReserved(page);
+ for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
+ /*
+ * 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
+ * too. Otherwse drivers using get_user_pages() to access tail
+ * 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);
+ set_page_count(p, 0);
+ p->first_page = page;
+ /* Make sure p->first_page is always valid for PageTail() */
+ smp_wmb();
+ __SetPageTail(p);
+ }
+}
+
+/*
+ * PageHuge() only returns true for hugetlbfs pages, but not for normal or
+ * transparent huge pages. See the PageTransHuge() documentation for more
+ * details.
+ */
+int PageHuge(struct page *page)
+{
+ if (!PageCompound(page))
+ return 0;
+
+ page = compound_head(page);
+ return get_compound_page_dtor(page) == free_huge_page;
+}
+EXPORT_SYMBOL_GPL(PageHuge);
+
+/*
+ * 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;
+
+ return get_compound_page_dtor(page_head) == free_huge_page;
+}
+
+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;
+}
+
+static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
+{
+ struct page *page;
+
+ page = alloc_pages_exact_node(nid,
+ htlb_alloc_mask(h)|__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;
+}
+
+static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
+{
+ struct page *page;
+ int nr_nodes, node;
+ int ret = 0;
+
+ for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
+ page = alloc_fresh_huge_page_node(h, node);
+ if (page) {
+ ret = 1;
+ break;
+ }
+ }
+
+ if (ret)
+ count_vm_event(HTLB_BUDDY_PGALLOC);
+ else
+ count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
+
+ return ret;
+}
+
+/*
+ * 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 nr_nodes, node;
+ int ret = 0;
+
+ for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
+ /*
+ * If we're returning unused surplus pages, only examine
+ * nodes with surplus pages.
+ */
+ if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
+ !list_empty(&h->hugepage_freelists[node])) {
+ struct page *page =
+ list_entry(h->hugepage_freelists[node].next,
+ struct page, lru);
+ list_del(&page->lru);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[node]--;
+ if (acct_surplus) {
+ h->surplus_huge_pages--;
+ h->surplus_huge_pages_node[node]--;
+ }
+ update_and_free_page(h, page);
+ ret = 1;
+ break;
+ }
+ }
+
+ return ret;
+}
+
+/*
+ * Dissolve a given free hugepage into free buddy pages. This function does
+ * nothing for in-use (including surplus) hugepages.
+ */
+static void dissolve_free_huge_page(struct page *page)
+{
+ spin_lock(&hugetlb_lock);
+ if (PageHuge(page) && !page_count(page)) {
+ struct hstate *h = page_hstate(page);
+ int nid = page_to_nid(page);
+ list_del(&page->lru);
+ h->free_huge_pages--;
+ h->free_huge_pages_node[nid]--;
+ update_and_free_page(h, page);
+ }
+ spin_unlock(&hugetlb_lock);
+}
+
+/*
+ * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
+ * make specified memory blocks removable from the system.
+ * Note that start_pfn should aligned with (minimum) hugepage size.
+ */
+void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
+{
+ unsigned int order = 8 * sizeof(void *);
+ unsigned long pfn;
+ struct hstate *h;
+
+ if (!hugepages_supported())
+ return;
+
+ /* Set scan step to minimum hugepage size */
+ for_each_hstate(h)
+ if (order > huge_page_order(h))
+ order = huge_page_order(h);
+ VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order));
+ for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order)
+ dissolve_free_huge_page(pfn_to_page(pfn));
+}
+
+static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
+{
+ struct page *page;
+ unsigned int r_nid;
+
+ if (hstate_is_gigantic(h))
+ 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(h)|__GFP_COMP|
+ __GFP_REPEAT|__GFP_NOWARN,
+ huge_page_order(h));
+ else
+ page = alloc_pages_exact_node(nid,
+ htlb_alloc_mask(h)|__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));
+ page = NULL;
+ }
+
+ spin_lock(&hugetlb_lock);
+ if (page) {
+ INIT_LIST_HEAD(&page->lru);
+ r_nid = page_to_nid(page);
+ set_compound_page_dtor(page, free_huge_page);
+ set_hugetlb_cgroup(page, NULL);
+ /*
+ * 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 = NULL;
+
+ spin_lock(&hugetlb_lock);
+ if (h->free_huge_pages - h->resv_huge_pages > 0)
+ 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;
+ bool alloc_ok = true;
+
+ 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) {
+ alloc_ok = false;
+ break;
+ }
+ list_add(&page->lru, &surplus_list);
+ }
+ allocated += i;
+
+ /*
+ * 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) {
+ 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;
+ }
+ /*
+ * 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;
+ /*
+ * 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(page_count(page), page);
+ enqueue_huge_page(h, page);
+ }
+free:
+ spin_unlock(&hugetlb_lock);
+
+ /* Free unnecessary surplus pages to the buddy allocator */
+ list_for_each_entry_safe(page, tmp, &surplus_list, 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 (hstate_is_gigantic(h))
+ 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_MEMORY], 1))
+ break;
+ cond_resched_lock(&hugetlb_lock);
+ }
+}
+
+/*
+ * 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 subpool usage 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 allocated from the subpool and 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 resv_map *resv;
+ pgoff_t idx;
+ long chg;
+
+ resv = vma_resv_map(vma);
+ if (!resv)
+ return 1;
+
+ idx = vma_hugecache_offset(h, vma, addr);
+ chg = region_chg(resv, idx, idx + 1);
+
+ if (vma->vm_flags & VM_MAYSHARE)
+ return chg;
+ else
+ return chg < 0 ? chg : 0;
+}
+static void vma_commit_reservation(struct hstate *h,
+ struct vm_area_struct *vma, unsigned long addr)
+{
+ struct resv_map *resv;
+ pgoff_t idx;
+
+ resv = vma_resv_map(vma);
+ if (!resv)
+ return;
+
+ idx = vma_hugecache_offset(h, vma, addr);
+ region_add(resv, idx, idx + 1);
+}
+
+static struct page *alloc_huge_page(struct vm_area_struct *vma,
+ unsigned long addr, int avoid_reserve)
+{
+ struct hugepage_subpool *spool = subpool_vma(vma);
+ struct hstate *h = hstate_vma(vma);
+ struct page *page;
+ long chg;
+ int ret, idx;
+ struct hugetlb_cgroup *h_cg;
+
+ idx = hstate_index(h);
+ /*
+ * Processes that did not create the mapping will have no
+ * reserves and will not have accounted against subpool
+ * limit. Check that the subpool limit can be made before
+ * satisfying the allocation MAP_NORESERVE mappings may also
+ * need pages and subpool limit allocated allocated if no reserve
+ * mapping overlaps.
+ */
+ chg = vma_needs_reservation(h, vma, addr);
+ if (chg < 0)
+ return ERR_PTR(-ENOMEM);
+ if (chg || avoid_reserve)
+ if (hugepage_subpool_get_pages(spool, 1) < 0)
+ return ERR_PTR(-ENOSPC);
+
+ ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
+ if (ret)
+ goto out_subpool_put;
+
+ spin_lock(&hugetlb_lock);
+ page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);
+ if (!page) {
+ spin_unlock(&hugetlb_lock);
+ page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
+ if (!page)
+ goto out_uncharge_cgroup;
+
+ spin_lock(&hugetlb_lock);
+ list_move(&page->lru, &h->hugepage_activelist);
+ /* Fall through */
+ }
+ hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
+ spin_unlock(&hugetlb_lock);
+
+ set_page_private(page, (unsigned long)spool);
+
+ vma_commit_reservation(h, vma, addr);
+ return page;
+
+out_uncharge_cgroup:
+ hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
+out_subpool_put:
+ if (chg || avoid_reserve)
+ hugepage_subpool_put_pages(spool, 1);
+ return ERR_PTR(-ENOSPC);
+}
+
+/*
+ * alloc_huge_page()'s wrapper which simply returns the page if allocation
+ * succeeds, otherwise NULL. This function is called from new_vma_page(),
+ * where no ERR_VALUE is expected to be returned.
+ */
+struct page *alloc_huge_page_noerr(struct vm_area_struct *vma,
+ unsigned long addr, int avoid_reserve)
+{
+ struct page *page = alloc_huge_page(vma, addr, avoid_reserve);
+ if (IS_ERR(page))
+ page = NULL;
+ return page;
+}
+
+int __weak alloc_bootmem_huge_page(struct hstate *h)
+{
+ struct huge_bootmem_page *m;
+ int nr_nodes, node;
+
+ for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
+ void *addr;
+
+ addr = memblock_virt_alloc_try_nid_nopanic(
+ huge_page_size(h), huge_page_size(h),
+ 0, BOOTMEM_ALLOC_ACCESSIBLE, node);
+ 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;
+ }
+ }
+ return 0;
+
+found:
+ BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
+ /* 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 __init 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 hstate *h = m->hstate;
+ struct page *page;
+
+#ifdef CONFIG_HIGHMEM
+ page = pfn_to_page(m->phys >> PAGE_SHIFT);
+ memblock_free_late(__pa(m),
+ sizeof(struct huge_bootmem_page));
+#else
+ page = virt_to_page(m);
+#endif
+ WARN_ON(page_count(page) != 1);
+ prep_compound_huge_page(page, h->order);
+ WARN_ON(PageReserved(page));
+ 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 (hstate_is_gigantic(h))
+ adjust_managed_page_count(page, 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 (hstate_is_gigantic(h)) {
+ if (!alloc_bootmem_huge_page(h))
+ break;
+ } else if (!alloc_fresh_huge_page(h,
+ &node_states[N_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 (!hstate_is_gigantic(h))
+ 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];
+ pr_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 (hstate_is_gigantic(h))
+ 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 nr_nodes, node;
+
+ VM_BUG_ON(delta != -1 && delta != 1);
+
+ if (delta < 0) {
+ for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
+ if (h->surplus_huge_pages_node[node])
+ goto found;
+ }
+ } 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;
+ }
+ }
+ return 0;
+
+found:
+ h->surplus_huge_pages += delta;
+ h->surplus_huge_pages_node[node] += delta;
+ return 1;
+}
+
+#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 (hstate_is_gigantic(h) && !gigantic_page_supported())
+ 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);
+ if (hstate_is_gigantic(h))
+ ret = alloc_fresh_gigantic_page(h, nodes_allowed);
+ else
+ 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;
+ cond_resched_lock(&hugetlb_lock);
+ }
+ 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 hstate *h, int nid,
+ unsigned long count, size_t len)
+{
+ int err;
+ NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
+
+ if (hstate_is_gigantic(h) && !gigantic_page_supported()) {
+ 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_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_MEMORY];
+
+ h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
+
+ if (nodes_allowed != &node_states[N_MEMORY])
+ NODEMASK_FREE(nodes_allowed);
+
+ return len;
+out:
+ NODEMASK_FREE(nodes_allowed);
+ return err;
+}
+
+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);
+}
+
+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, 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, 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 (hstate_is_gigantic(h))
+ return -EINVAL;
+
+ err = kstrtoul(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 = hstate_index(h);
+
+ 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)
+ pr_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 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
+ * 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 devices
+ */
+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 device 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 device.
+ * No-op if no hstate attributes attached.
+ */
+static void hugetlb_unregister_node(struct node *node)
+{
+ struct hstate *h;
+ struct node_hstate *nhs = &node_hstates[node->dev.id];
+
+ if (!nhs->hugepages_kobj)
+ return; /* no hstate attributes */
+
+ 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;
+ }
+ }
+
+ kobject_put(nhs->hugepages_kobj);
+ nhs->hugepages_kobj = NULL;
+}
+
+/*
+ * hugetlb module exit: unregister hstate attributes from node devices
+ * that have them.
+ */
+static void hugetlb_unregister_all_nodes(void)
+{
+ int nid;
+
+ /*
+ * disable node device 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 device.
+ * No-op if attributes already registered.
+ */
+static void hugetlb_register_node(struct node *node)
+{
+ struct hstate *h;
+ struct node_hstate *nhs = &node_hstates[node->dev.id];
+ int err;
+
+ if (nhs->hugepages_kobj)
+ return; /* already allocated */
+
+ nhs->hugepages_kobj = kobject_create_and_add("hugepages",
+ &node->dev.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) {
+ pr_err("Hugetlb: Unable to add hstate %s for node %d\n",
+ h->name, node->dev.id);
+ hugetlb_unregister_node(node);
+ break;
+ }
+ }
+}
+
+/*
+ * hugetlb init time: register hstate attributes for all registered node
+ * devices of nodes that have memory. All on-line nodes should have
+ * registered their associated device by this time.
+ */
+static void __init hugetlb_register_all_nodes(void)
+{
+ int nid;
+
+ for_each_node_state(nid, N_MEMORY) {
+ struct node *node = node_devices[nid];
+ if (node->dev.id == nid)
+ hugetlb_register_node(node);
+ }
+
+ /*
+ * Let the node device 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[hstate_index(h)]);
+ }
+
+ kobject_put(hugepages_kobj);
+ kfree(htlb_fault_mutex_table);
+}
+module_exit(hugetlb_exit);
+
+static int __init hugetlb_init(void)
+{
+ int i;
+
+ if (!hugepages_supported())
+ 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 = hstate_index(size_to_hstate(default_hstate_size));
+ 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();
+ hugetlb_cgroup_file_init();
+
+#ifdef CONFIG_SMP
+ num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
+#else
+ num_fault_mutexes = 1;
+#endif
+ htlb_fault_mutex_table =
+ kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL);
+ BUG_ON(!htlb_fault_mutex_table);
+
+ for (i = 0; i < num_fault_mutexes; i++)
+ mutex_init(&htlb_fault_mutex_table[i]);
+ 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)) {
+ pr_warning("hugepagesz= specified twice, ignoring\n");
+ return;
+ }
+ BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
+ BUG_ON(order == 0);
+ h = &hstates[hugetlb_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]);
+ INIT_LIST_HEAD(&h->hugepage_activelist);
+ h->next_nid_to_alloc = first_node(node_states[N_MEMORY]);
+ h->next_nid_to_free = first_node(node_states[N_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;
+
+ /*
+ * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet,
+ * so this hugepages= parameter goes to the "default hstate".
+ */
+ if (!hugetlb_max_hstate)
+ mhp = &default_hstate_max_huge_pages;
+ else
+ mhp = &parsed_hstate->max_huge_pages;
+
+ if (mhp == last_mhp) {
+ pr_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 (hugetlb_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 = h->max_huge_pages;
+ int ret;
+
+ if (!hugepages_supported())
+ return -ENOTSUPP;
+
+ table->data = &tmp;
+ table->maxlen = sizeof(unsigned long);
+ ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
+ if (ret)
+ goto out;
+
+ if (write)
+ ret = __nr_hugepages_store_common(obey_mempolicy, h,
+ NUMA_NO_NODE, tmp, *length);
+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_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;
+
+ if (!hugepages_supported())
+ return -ENOTSUPP;
+
+ tmp = h->nr_overcommit_huge_pages;
+
+ if (write && hstate_is_gigantic(h))
+ 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;
+ if (!hugepages_supported())
+ return;
+ 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;
+ if (!hugepages_supported())
+ return 0;
+ 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]);
+}
+
+void hugetlb_show_meminfo(void)
+{
+ struct hstate *h;
+ int nid;
+
+ if (!hugepages_supported())
+ return;
+
+ 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));
+}
+
+/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
+unsigned long hugetlb_total_pages(void)
+{
+ 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;
+}
+
+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 *resv = 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 (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
+ kref_get(&resv->refs);
+}
+
+static void hugetlb_vm_op_close(struct vm_area_struct *vma)
+{
+ struct hstate *h = hstate_vma(vma);
+ struct resv_map *resv = vma_resv_map(vma);
+ struct hugepage_subpool *spool = subpool_vma(vma);
+ unsigned long reserve, start, end;
+ long gbl_reserve;
+
+ if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
+ return;
+
+ start = vma_hugecache_offset(h, vma, vma->vm_start);
+ end = vma_hugecache_offset(h, vma, vma->vm_end);
+
+ reserve = (end - start) - region_count(resv, start, end);
+
+ kref_put(&resv->refs, resv_map_release);
+
+ if (reserve) {
+ /*
+ * 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);
+ }
+}
+
+/*
+ * 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 = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
+ vma->vm_page_prot)));
+ } else {
+ entry = huge_pte_wrprotect(mk_huge_pte(page,
+ vma->vm_page_prot));
+ }
+ entry = pte_mkyoung(entry);
+ entry = pte_mkhuge(entry);
+ entry = arch_make_huge_pte(entry, vma, page, writable);
+
+ return entry;
+}
+
+static void set_huge_ptep_writable(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep)
+{
+ pte_t entry;
+
+ entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
+ if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
+ update_mmu_cache(vma, address, ptep);
+}
+
+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;
+}
+
+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);
+ unsigned long mmun_start; /* For mmu_notifiers */
+ unsigned long mmun_end; /* For mmu_notifiers */
+ int ret = 0;
+
+ cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
+
+ mmun_start = vma->vm_start;
+ mmun_end = vma->vm_end;
+ if (cow)
+ mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end);
+
+ for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
+ spinlock_t *src_ptl, *dst_ptl;
+ src_pte = huge_pte_offset(src, addr);
+ if (!src_pte)
+ continue;
+ dst_pte = huge_pte_alloc(dst, addr, sz);
+ if (!dst_pte) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ /* If the pagetables are shared don't copy or take references */
+ if (dst_pte == src_pte)
+ continue;
+
+ 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);
+ entry = huge_ptep_get(src_pte);
+ if (huge_pte_none(entry)) { /* skip none entry */
+ ;
+ } 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);
+ set_huge_pte_at(src, addr, src_pte, entry);
+ }
+ set_huge_pte_at(dst, addr, dst_pte, entry);
+ } else {
+ if (cow) {
+ huge_ptep_set_wrprotect(src, addr, src_pte);
+ mmu_notifier_invalidate_range(src, mmun_start,
+ mmun_end);
+ }
+ 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_ptl);
+ spin_unlock(dst_ptl);
+ }
+
+ if (cow)
+ mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end);
+
+ return ret;
+}
+
+void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
+ unsigned long start, unsigned long end,
+ struct page *ref_page)
+{
+ int force_flush = 0;
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long address;
+ pte_t *ptep;
+ pte_t pte;
+ spinlock_t *ptl;
+ struct page *page;
+ struct hstate *h = hstate_vma(vma);
+ unsigned long sz = huge_page_size(h);
+ const unsigned long mmun_start = start; /* For mmu_notifiers */
+ const unsigned long mmun_end = end; /* For mmu_notifiers */
+
+ WARN_ON(!is_vm_hugetlb_page(vma));
+ BUG_ON(start & ~huge_page_mask(h));
+ BUG_ON(end & ~huge_page_mask(h));
+
+ tlb_start_vma(tlb, vma);
+ mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
+ address = start;
+again:
+ for (; address < end; address += sz) {
+ ptep = huge_pte_offset(mm, address);
+ if (!ptep)
+ continue;
+
+ ptl = huge_pte_lock(h, mm, ptep);
+ if (huge_pmd_unshare(mm, &address, ptep))
+ goto unlock;
+
+ pte = huge_ptep_get(ptep);
+ if (huge_pte_none(pte))
+ goto unlock;
+
+ /*
+ * Migrating hugepage or HWPoisoned hugepage is already
+ * unmapped and its refcount is dropped, so just clear pte here.
+ */
+ if (unlikely(!pte_present(pte))) {
+ huge_pte_clear(mm, address, ptep);
+ goto unlock;
+ }
+
+ page = pte_page(pte);
+ /*
+ * 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) {
+ if (page != ref_page)
+ goto unlock;
+
+ /*
+ * 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);
+ tlb_remove_tlb_entry(tlb, ptep, address);
+ if (huge_pte_dirty(pte))
+ set_page_dirty(page);
+
+ page_remove_rmap(page);
+ force_flush = !__tlb_remove_page(tlb, page);
+ if (force_flush) {
+ address += sz;
+ spin_unlock(ptl);
+ break;
+ }
+ /* Bail out after unmapping reference page if supplied */
+ if (ref_page) {
+ spin_unlock(ptl);
+ break;
+ }
+unlock:
+ spin_unlock(ptl);
+ }
+ /*
+ * mmu_gather ran out of room to batch pages, we break out of
+ * the PTE lock to avoid doing the potential expensive TLB invalidate
+ * and page-free while holding it.
+ */
+ if (force_flush) {
+ force_flush = 0;
+ tlb_flush_mmu(tlb);
+ if (address < end && !ref_page)
+ goto again;
+ }
+ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+ tlb_end_vma(tlb, vma);
+}
+
+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
+ * is to clear it before releasing the i_mmap_rwsem. This works
+ * because in the context this is called, the VMA is about to be
+ * destroyed and the i_mmap_rwsem is held.
+ */
+ vma->vm_flags &= ~VM_MAYSHARE;
+}
+
+void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, struct page *ref_page)
+{
+ struct mm_struct *mm;
+ struct mmu_gather tlb;
+
+ mm = vma->vm_mm;
+
+ tlb_gather_mmu(&tlb, mm, start, end);
+ __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
+ tlb_finish_mmu(&tlb, start, end);
+}
+
+/*
+ * 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 void 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;
+ 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;
+ mapping = file_inode(vma->vm_file)->i_mapping;
+
+ /*
+ * 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
+ */
+ i_mmap_lock_write(mapping);
+ vma_interval_tree_foreach(iter_vma, &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);
+ }
+ i_mmap_unlock_write(mapping);
+}
+
+/*
+ * Hugetlb_cow() should be called with page lock of the original hugepage held.
+ * 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.
+ */
+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, spinlock_t *ptl)
+{
+ struct hstate *h = hstate_vma(vma);
+ struct page *old_page, *new_page;
+ int ret = 0, outside_reserve = 0;
+ unsigned long mmun_start; /* For mmu_notifiers */
+ unsigned long mmun_end; /* For mmu_notifiers */
+
+ 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 */
+ if (page_mapcount(old_page) == 1 && 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 (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. It will
+ * be acquired again before returning to the caller, as expected.
+ */
+ spin_unlock(ptl);
+ new_page = alloc_huge_page(vma, address, outside_reserve);
+
+ if (IS_ERR(new_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) {
+ page_cache_release(old_page);
+ BUG_ON(huge_pte_none(pte));
+ unmap_ref_private(mm, vma, old_page, address);
+ BUG_ON(huge_pte_none(pte));
+ spin_lock(ptl);
+ ptep = huge_pte_offset(mm, address & huge_page_mask(h));
+ 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;
+ }
+
+ ret = (PTR_ERR(new_page) == -ENOMEM) ?
+ VM_FAULT_OOM : VM_FAULT_SIGBUS;
+ goto out_release_old;
+ }
+
+ /*
+ * When the original hugepage is shared one, it does not have
+ * anon_vma prepared.
+ */
+ if (unlikely(anon_vma_prepare(vma))) {
+ ret = VM_FAULT_OOM;
+ goto out_release_all;
+ }
+
+ copy_user_huge_page(new_page, old_page, address, vma,
+ pages_per_huge_page(h));
+ __SetPageUptodate(new_page);
+ set_page_huge_active(new_page);
+
+ mmun_start = address & huge_page_mask(h);
+ mmun_end = mmun_start + huge_page_size(h);
+ mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
+
+ /*
+ * Retake the page table lock to check for racing updates
+ * before the page tables are altered
+ */
+ spin_lock(ptl);
+ ptep = huge_pte_offset(mm, address & huge_page_mask(h));
+ if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
+ ClearPagePrivate(new_page);
+
+ /* Break COW */
+ huge_ptep_clear_flush(vma, address, ptep);
+ mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
+ 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;
+ }
+ spin_unlock(ptl);
+ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+out_release_all:
+ page_cache_release(new_page);
+out_release_old:
+ page_cache_release(old_page);
+
+ spin_lock(ptl); /* Caller expects lock to be held */
+ return ret;
+}
+
+/* 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,
+ struct address_space *mapping, pgoff_t idx,
+ unsigned long address, pte_t *ptep, unsigned int flags)
+{
+ struct hstate *h = hstate_vma(vma);
+ int ret = VM_FAULT_SIGBUS;
+ int anon_rmap = 0;
+ unsigned long size;
+ struct page *page;
+ pte_t new_pte;
+ spinlock_t *ptl;
+
+ /*
+ * 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)) {
+ pr_warning("PID %d killed due to inadequate hugepage pool\n",
+ current->pid);
+ return ret;
+ }
+
+ /*
+ * 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);
+ if (ret == -ENOMEM)
+ ret = VM_FAULT_OOM;
+ else
+ ret = VM_FAULT_SIGBUS;
+ goto out;
+ }
+ clear_huge_page(page, address, pages_per_huge_page(h));
+ __SetPageUptodate(page);
+ set_page_huge_active(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;
+ }
+ ClearPagePrivate(page);
+
+ spin_lock(&inode->i_lock);
+ inode->i_blocks += blocks_per_huge_page(h);
+ spin_unlock(&inode->i_lock);
+ } else {
+ lock_page(page);
+ if (unlikely(anon_vma_prepare(vma))) {
+ ret = VM_FAULT_OOM;
+ goto backout_unlocked;
+ }
+ anon_rmap = 1;
+ }
+ } 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(hstate_index(h));
+ goto backout_unlocked;
+ }
+ }
+
+ /*
+ * 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;
+ }
+
+ ptl = huge_pte_lockptr(h, mm, ptep);
+ spin_lock(ptl);
+ 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;
+
+ if (anon_rmap) {
+ ClearPagePrivate(page);
+ hugepage_add_new_anon_rmap(page, vma, address);
+ } else
+ page_dup_rmap(page);
+ 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, ptl);
+ }
+
+ spin_unlock(ptl);
+ unlock_page(page);
+out:
+ return ret;
+
+backout:
+ spin_unlock(ptl);
+backout_unlocked:
+ unlock_page(page);
+ put_page(page);
+ goto out;
+}
+
+#ifdef CONFIG_SMP
+static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ struct address_space *mapping,
+ pgoff_t idx, unsigned long address)
+{
+ unsigned long key[2];
+ u32 hash;
+
+ if (vma->vm_flags & VM_SHARED) {
+ key[0] = (unsigned long) mapping;
+ key[1] = idx;
+ } else {
+ key[0] = (unsigned long) mm;
+ key[1] = address >> huge_page_shift(h);
+ }
+
+ hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0);
+
+ 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.
+ */
+static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ struct address_space *mapping,
+ pgoff_t idx, unsigned long address)
+{
+ return 0;
+}
+#endif
+
+int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long address, unsigned int flags)
+{
+ pte_t *ptep, entry;
+ spinlock_t *ptl;
+ int ret;
+ u32 hash;
+ pgoff_t idx;
+ struct page *page = NULL;
+ struct page *pagecache_page = NULL;
+ struct hstate *h = hstate_vma(vma);
+ struct address_space *mapping;
+ int need_wait_lock = 0;
+
+ address &= huge_page_mask(h);
+
+ ptep = huge_pte_offset(mm, address);
+ if (ptep) {
+ entry = huge_ptep_get(ptep);
+ if (unlikely(is_hugetlb_entry_migration(entry))) {
+ migration_entry_wait_huge(vma, mm, ptep);
+ return 0;
+ } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
+ return VM_FAULT_HWPOISON_LARGE |
+ VM_FAULT_SET_HINDEX(hstate_index(h));
+ }
+
+ ptep = huge_pte_alloc(mm, address, huge_page_size(h));
+ if (!ptep)
+ return VM_FAULT_OOM;
+
+ mapping = vma->vm_file->f_mapping;
+ idx = vma_hugecache_offset(h, vma, address);
+
+ /*
+ * 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.
+ */
+ hash = fault_mutex_hash(h, mm, vma, mapping, idx, address);
+ mutex_lock(&htlb_fault_mutex_table[hash]);
+
+ entry = huge_ptep_get(ptep);
+ if (huge_pte_none(entry)) {
+ ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
+ goto out_mutex;
+ }
+
+ ret = 0;
+
+ /*
+ * entry could be a migration/hwpoison entry at this point, so this
+ * check prevents the kernel from going below assuming that we have
+ * a active hugepage in pagecache. This goto expects the 2nd page fault,
+ * and is_hugetlb_entry_(migration|hwpoisoned) check will properly
+ * handle it.
+ */
+ if (!pte_present(entry))
+ goto out_mutex;
+
+ /*
+ * 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) && !huge_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);
+ }
+
+ 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;
+
+ /*
+ * 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)
+ if (!trylock_page(page)) {
+ need_wait_lock = 1;
+ goto out_ptl;
+ }
+
+ get_page(page);
+
+ if (flags & FAULT_FLAG_WRITE) {
+ if (!huge_pte_write(entry)) {
+ ret = hugetlb_cow(mm, vma, address, ptep, entry,
+ pagecache_page, ptl);
+ goto out_put_page;
+ }
+ entry = huge_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_put_page:
+ if (page != pagecache_page)
+ unlock_page(page);
+ put_page(page);
+out_ptl:
+ spin_unlock(ptl);
+
+ if (pagecache_page) {
+ unlock_page(pagecache_page);
+ put_page(pagecache_page);
+ }
+out_mutex:
+ mutex_unlock(&htlb_fault_mutex_table[hash]);
+ /*
+ * 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);
+ return ret;
+}
+
+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,
+ long i, unsigned int flags)
+{
+ unsigned long pfn_offset;
+ unsigned long vaddr = *position;
+ unsigned long remainder = *nr_pages;
+ struct hstate *h = hstate_vma(vma);
+
+ while (vaddr < vma->vm_end && remainder) {
+ pte_t *pte;
+ spinlock_t *ptl = NULL;
+ int absent;
+ struct page *page;
+
+ /*
+ * If we have a pending SIGKILL, don't keep faulting pages and
+ * potentially allocating memory.
+ */
+ if (unlikely(fatal_signal_pending(current))) {
+ remainder = 0;
+ break;
+ }
+
+ /*
+ * 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.
+ *
+ * Note that page table lock is not held when pte is null.
+ */
+ pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
+ if (pte)
+ ptl = huge_pte_lock(h, mm, pte);
+ 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)) {
+ if (pte)
+ spin_unlock(ptl);
+ remainder = 0;
+ break;
+ }
+
+ /*
+ * 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)) ||
+ ((flags & FOLL_WRITE) &&
+ !huge_pte_write(huge_ptep_get(pte)))) {
+ int ret;
+
+ if (pte)
+ spin_unlock(ptl);
+ ret = hugetlb_fault(mm, vma, vaddr,
+ (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
+ 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_foll(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(ptl);
+ }
+ *nr_pages = remainder;
+ *position = vaddr;
+
+ return i ? i : -EFAULT;
+}
+
+unsigned long 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);
+ unsigned long pages = 0;
+
+ BUG_ON(address >= end);
+ flush_cache_range(vma, address, end);
+
+ mmu_notifier_invalidate_range_start(mm, start, end);
+ i_mmap_lock_write(vma->vm_file->f_mapping);
+ for (; address < end; address += huge_page_size(h)) {
+ spinlock_t *ptl;
+ ptep = huge_pte_offset(mm, address);
+ if (!ptep)
+ continue;
+ ptl = huge_pte_lock(h, mm, ptep);
+ if (huge_pmd_unshare(mm, &address, ptep)) {
+ pages++;
+ spin_unlock(ptl);
+ continue;
+ }
+ 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);
+ set_huge_pte_at(mm, address, ptep, newpte);
+ pages++;
+ }
+ spin_unlock(ptl);
+ continue;
+ }
+ if (!huge_pte_none(pte)) {
+ pte = huge_ptep_get_and_clear(mm, address, ptep);
+ pte = pte_mkhuge(huge_pte_modify(pte, newprot));
+ pte = arch_make_huge_pte(pte, vma, NULL, 0);
+ set_huge_pte_at(mm, address, ptep, pte);
+ pages++;
+ }
+ spin_unlock(ptl);
+ }
+ /*
+ * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
+ * may have cleared our pud entry and done put_page on the page table:
+ * once we release i_mmap_rwsem, another task can do the final put_page
+ * and that page table be reused and filled with junk.
+ */
+ flush_tlb_range(vma, start, end);
+ mmu_notifier_invalidate_range(mm, start, end);
+ i_mmap_unlock_write(vma->vm_file->f_mapping);
+ mmu_notifier_invalidate_range_end(mm, start, end);
+
+ return pages << h->order;
+}
+
+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);
+ struct hugepage_subpool *spool = subpool_inode(inode);
+ struct resv_map *resv_map;
+ long gbl_reserve;
+
+ /*
+ * Only apply hugepage reservation if asked. At fault time, an
+ * attempt will be made for VM_NORESERVE to allocate a page
+ * 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) {
+ resv_map = inode_resv_map(inode);
+
+ chg = region_chg(resv_map, from, to);
+
+ } else {
+ 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 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) {
+ ret = -ENOSPC;
+ goto out_err;
+ }
+
+ /*
+ * Check enough hugepages are available for the reservation.
+ * Hand the pages back to the subpool if there are not
+ */
+ ret = hugetlb_acct_memory(h, gbl_reserve);
+ if (ret < 0) {
+ /* put back original number of pages, chg */
+ (void)hugepage_subpool_put_pages(spool, 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(resv_map, from, to);
+ return 0;
+out_err:
+ if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
+ kref_put(&resv_map->refs, resv_map_release);
+ return ret;
+}
+
+void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
+{
+ struct hstate *h = hstate_inode(inode);
+ struct resv_map *resv_map = inode_resv_map(inode);
+ long chg = 0;
+ struct hugepage_subpool *spool = subpool_inode(inode);
+ long gbl_reserve;
+
+ if (resv_map)
+ chg = region_truncate(resv_map, offset);
+ spin_lock(&inode->i_lock);
+ inode->i_blocks -= (blocks_per_huge_page(h) * freed);
+ spin_unlock(&inode->i_lock);
+
+ /*
+ * 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);
+}
+
+#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 */
+ unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED;
+ unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED;
+
+ /*
+ * 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;
+}
+
+static int vma_shareable(struct vm_area_struct *vma, unsigned long addr)
+{
+ unsigned long base = addr & PUD_MASK;
+ unsigned long end = base + PUD_SIZE;
+
+ /*
+ * check on proper vm_flags and page table alignment
+ */
+ if (vma->vm_flags & VM_MAYSHARE &&
+ vma->vm_start <= base && end <= vma->vm_end)
+ return 1;
+ return 0;
+}
+
+/*
+ * 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
+ * code much cleaner. pmd allocation is essential for the shared case because
+ * pud has to be populated inside the same i_mmap_rwsem section - otherwise
+ * racing tasks could either miss the sharing (see huge_pte_offset) or select a
+ * bad pmd for sharing.
+ */
+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;
+ spinlock_t *ptl;
+
+ if (!vma_shareable(vma, addr))
+ return (pte_t *)pmd_alloc(mm, pud, addr);
+
+ i_mmap_lock_write(mapping);
+ vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
+ if (svma == vma)
+ continue;
+
+ saddr = page_table_shareable(svma, vma, addr, idx);
+ if (saddr) {
+ spte = huge_pte_offset(svma->vm_mm, saddr);
+ if (spte) {
+ mm_inc_nr_pmds(mm);
+ get_page(virt_to_page(spte));
+ break;
+ }
+ }
+ }
+
+ if (!spte)
+ goto out;
+
+ ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
+ spin_lock(ptl);
+ if (pud_none(*pud)) {
+ pud_populate(mm, pud,
+ (pmd_t *)((unsigned long)spte & PAGE_MASK));
+ } else {
+ put_page(virt_to_page(spte));
+ mm_inc_nr_pmds(mm);
+ }
+ spin_unlock(ptl);
+out:
+ pte = (pte_t *)pmd_alloc(mm, pud, addr);
+ i_mmap_unlock_write(mapping);
+ 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.
+ *
+ * called with page table lock held.
+ *
+ * returns: 1 successfully unmapped a shared pte page
+ * 0 the underlying pte page is not shared, or it is the last user
+ */
+int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
+{
+ pgd_t *pgd = pgd_offset(mm, *addr);
+ pud_t *pud = pud_offset(pgd, *addr);
+
+ 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));
+ mm_dec_nr_pmds(mm);
+ *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
+ return 1;
+}
+#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;
+}
+#define want_pmd_share() (0)
+#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
+
+#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+ unsigned long addr, unsigned long sz)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pte_t *pte = NULL;
+
+ pgd = pgd_offset(mm, addr);
+ pud = pud_alloc(mm, pgd, addr);
+ 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);
+ }
+ }
+ BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte));
+
+ return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd = NULL;
+
+ pgd = pgd_offset(mm, addr);
+ if (pgd_present(*pgd)) {
+ pud = pud_offset(pgd, addr);
+ if (pud_present(*pud)) {
+ if (pud_huge(*pud))
+ return (pte_t *)pud;
+ pmd = pmd_offset(pud, addr);
+ }
+ }
+ return (pte_t *) pmd;
+}
+
+#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);
+}
+
+struct page * __weak
+follow_huge_pmd(struct mm_struct *mm, unsigned long address,
+ pmd_t *pmd, int flags)
+{
+ struct page *page = NULL;
+ spinlock_t *ptl;
+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;
+ if (pmd_present(*pmd)) {
+ page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
+ if (flags & FOLL_GET)
+ get_page(page);
+ } else {
+ if (is_hugetlb_entry_migration(huge_ptep_get((pte_t *)pmd))) {
+ 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);
+ return page;
+}
+
+struct page * __weak
+follow_huge_pud(struct mm_struct *mm, unsigned long address,
+ pud_t *pud, int flags)
+{
+ if (flags & FOLL_GET)
+ return NULL;
+
+ return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
+}
+
+#ifdef CONFIG_MEMORY_FAILURE
+
+/*
+ * 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);
+ /*
+ * Just checking !page_huge_active is not enough, because that could be
+ * an isolated/hwpoisoned hugepage (which have >0 refcount).
+ */
+ if (!page_huge_active(hpage) && !page_count(hpage)) {
+ /*
+ * Hwpoisoned hugepage isn't linked to activelist or freelist,
+ * but dangling hpage->lru can trigger list-debug warnings
+ * (this happens when we call unpoison_memory() on it),
+ * so let it point to itself with list_del_init().
+ */
+ list_del_init(&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
+
+bool isolate_huge_page(struct page *page, struct list_head *list)
+{
+ bool ret = true;
+
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+ spin_lock(&hugetlb_lock);
+ if (!page_huge_active(page) || !get_page_unless_zero(page)) {
+ ret = false;
+ goto unlock;
+ }
+ clear_page_huge_active(page);
+ list_move_tail(&page->lru, list);
+unlock:
+ spin_unlock(&hugetlb_lock);
+ return ret;
+}
+
+void putback_active_hugepage(struct page *page)
+{
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+ spin_lock(&hugetlb_lock);
+ set_page_huge_active(page);
+ list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
+ spin_unlock(&hugetlb_lock);
+ put_page(page);
+}
Code Review / kvmfornfv.git / blobdiff