diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 5788 |
1 files changed, 5788 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c new file mode 100644 index 000000000..81949f6d2 --- /dev/null +++ b/mm/hugetlb.c @@ -0,0 +1,5788 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Generic hugetlb support. + * (C) Nadia Yvette Chambers, April 2004 + */ +#include <linux/list.h> +#include <linux/init.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/memblock.h> +#include <linux/sysfs.h> +#include <linux/slab.h> +#include <linux/sched/mm.h> +#include <linux/mmdebug.h> +#include <linux/sched/signal.h> +#include <linux/rmap.h> +#include <linux/string_helpers.h> +#include <linux/swap.h> +#include <linux/swapops.h> +#include <linux/jhash.h> +#include <linux/numa.h> +#include <linux/llist.h> +#include <linux/cma.h> + +#include <asm/page.h> +#include <asm/pgalloc.h> +#include <asm/tlb.h> + +#include <linux/io.h> +#include <linux/hugetlb.h> +#include <linux/hugetlb_cgroup.h> +#include <linux/node.h> +#include <linux/userfaultfd_k.h> +#include <linux/page_owner.h> +#include "internal.h" + +int hugetlb_max_hstate __read_mostly; +unsigned int default_hstate_idx; +struct hstate hstates[HUGE_MAX_HSTATE]; + +#ifdef CONFIG_CMA +static struct cma *hugetlb_cma[MAX_NUMNODES]; +#endif +static unsigned long hugetlb_cma_size __initdata; + +/* + * Minimum page order among possible hugepage sizes, set to a proper value + * at boot time. + */ +static unsigned int minimum_order __read_mostly = UINT_MAX; + +__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 bool __initdata parsed_valid_hugepagesz = true; +static bool __initdata parsed_default_hugepagesz; + +/* + * 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; +struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp; + +static inline bool PageHugeFreed(struct page *head) +{ + return page_private(head + 4) == -1UL; +} + +static inline void SetPageHugeFreed(struct page *head) +{ + set_page_private(head + 4, -1UL); +} + +static inline void ClearPageHugeFreed(struct page *head) +{ + set_page_private(head + 4, 0); +} + +/* 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 based 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 + * 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 maintained. + */ +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; + } + } + + /* minimum size accounting */ + if (spool->min_hpages != -1 && spool->rsv_hpages) { + 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; + + /* minimum size accounting */ + if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) { + 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)); +} + +/* Helper that removes a struct file_region from the resv_map cache and returns + * it for use. + */ +static struct file_region * +get_file_region_entry_from_cache(struct resv_map *resv, long from, long to) +{ + struct file_region *nrg = NULL; + + VM_BUG_ON(resv->region_cache_count <= 0); + + resv->region_cache_count--; + nrg = list_first_entry(&resv->region_cache, struct file_region, link); + list_del(&nrg->link); + + nrg->from = from; + nrg->to = to; + + return nrg; +} + +static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg, + struct file_region *rg) +{ +#ifdef CONFIG_CGROUP_HUGETLB + nrg->reservation_counter = rg->reservation_counter; + nrg->css = rg->css; + if (rg->css) + css_get(rg->css); +#endif +} + +/* Helper that records hugetlb_cgroup uncharge info. */ +static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg, + struct hstate *h, + struct resv_map *resv, + struct file_region *nrg) +{ +#ifdef CONFIG_CGROUP_HUGETLB + if (h_cg) { + nrg->reservation_counter = + &h_cg->rsvd_hugepage[hstate_index(h)]; + nrg->css = &h_cg->css; + /* + * The caller will hold exactly one h_cg->css reference for the + * whole contiguous reservation region. But this area might be + * scattered when there are already some file_regions reside in + * it. As a result, many file_regions may share only one css + * reference. In order to ensure that one file_region must hold + * exactly one h_cg->css reference, we should do css_get for + * each file_region and leave the reference held by caller + * untouched. + */ + css_get(&h_cg->css); + if (!resv->pages_per_hpage) + resv->pages_per_hpage = pages_per_huge_page(h); + /* pages_per_hpage should be the same for all entries in + * a resv_map. + */ + VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h)); + } else { + nrg->reservation_counter = NULL; + nrg->css = NULL; + } +#endif +} + +static void put_uncharge_info(struct file_region *rg) +{ +#ifdef CONFIG_CGROUP_HUGETLB + if (rg->css) + css_put(rg->css); +#endif +} + +static bool has_same_uncharge_info(struct file_region *rg, + struct file_region *org) +{ +#ifdef CONFIG_CGROUP_HUGETLB + return rg && org && + rg->reservation_counter == org->reservation_counter && + rg->css == org->css; + +#else + return true; +#endif +} + +static void coalesce_file_region(struct resv_map *resv, struct file_region *rg) +{ + struct file_region *nrg = NULL, *prg = NULL; + + prg = list_prev_entry(rg, link); + if (&prg->link != &resv->regions && prg->to == rg->from && + has_same_uncharge_info(prg, rg)) { + prg->to = rg->to; + + list_del(&rg->link); + put_uncharge_info(rg); + kfree(rg); + + rg = prg; + } + + nrg = list_next_entry(rg, link); + if (&nrg->link != &resv->regions && nrg->from == rg->to && + has_same_uncharge_info(nrg, rg)) { + nrg->from = rg->from; + + list_del(&rg->link); + put_uncharge_info(rg); + kfree(rg); + } +} + +/* + * Must be called with resv->lock held. + * + * Calling this with regions_needed != NULL will count the number of pages + * to be added but will not modify the linked list. And regions_needed will + * indicate the number of file_regions needed in the cache to carry out to add + * the regions for this range. + */ +static long add_reservation_in_range(struct resv_map *resv, long f, long t, + struct hugetlb_cgroup *h_cg, + struct hstate *h, long *regions_needed) +{ + long add = 0; + struct list_head *head = &resv->regions; + long last_accounted_offset = f; + struct file_region *rg = NULL, *trg = NULL, *nrg = NULL; + + if (regions_needed) + *regions_needed = 0; + + /* In this loop, we essentially handle an entry for the range + * [last_accounted_offset, rg->from), at every iteration, with some + * bounds checking. + */ + list_for_each_entry_safe(rg, trg, head, link) { + /* Skip irrelevant regions that start before our range. */ + if (rg->from < f) { + /* If this region ends after the last accounted offset, + * then we need to update last_accounted_offset. + */ + if (rg->to > last_accounted_offset) + last_accounted_offset = rg->to; + continue; + } + + /* When we find a region that starts beyond our range, we've + * finished. + */ + if (rg->from > t) + break; + + /* Add an entry for last_accounted_offset -> rg->from, and + * update last_accounted_offset. + */ + if (rg->from > last_accounted_offset) { + add += rg->from - last_accounted_offset; + if (!regions_needed) { + nrg = get_file_region_entry_from_cache( + resv, last_accounted_offset, rg->from); + record_hugetlb_cgroup_uncharge_info(h_cg, h, + resv, nrg); + list_add(&nrg->link, rg->link.prev); + coalesce_file_region(resv, nrg); + } else + *regions_needed += 1; + } + + last_accounted_offset = rg->to; + } + + /* Handle the case where our range extends beyond + * last_accounted_offset. + */ + if (last_accounted_offset < t) { + add += t - last_accounted_offset; + if (!regions_needed) { + nrg = get_file_region_entry_from_cache( + resv, last_accounted_offset, t); + record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg); + list_add(&nrg->link, rg->link.prev); + coalesce_file_region(resv, nrg); + } else + *regions_needed += 1; + } + + VM_BUG_ON(add < 0); + return add; +} + +/* Must be called with resv->lock acquired. Will drop lock to allocate entries. + */ +static int allocate_file_region_entries(struct resv_map *resv, + int regions_needed) + __must_hold(&resv->lock) +{ + struct list_head allocated_regions; + int to_allocate = 0, i = 0; + struct file_region *trg = NULL, *rg = NULL; + + VM_BUG_ON(regions_needed < 0); + + INIT_LIST_HEAD(&allocated_regions); + + /* + * Check for sufficient descriptors in the cache to accommodate + * the number of in progress add operations plus regions_needed. + * + * This is a while loop because when we drop the lock, some other call + * to region_add or region_del may have consumed some region_entries, + * so we keep looping here until we finally have enough entries for + * (adds_in_progress + regions_needed). + */ + while (resv->region_cache_count < + (resv->adds_in_progress + regions_needed)) { + to_allocate = resv->adds_in_progress + regions_needed - + resv->region_cache_count; + + /* At this point, we should have enough entries in the cache + * for all the existings adds_in_progress. We should only be + * needing to allocate for regions_needed. + */ + VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress); + + spin_unlock(&resv->lock); + for (i = 0; i < to_allocate; i++) { + trg = kmalloc(sizeof(*trg), GFP_KERNEL); + if (!trg) + goto out_of_memory; + list_add(&trg->link, &allocated_regions); + } + + spin_lock(&resv->lock); + + list_splice(&allocated_regions, &resv->region_cache); + resv->region_cache_count += to_allocate; + } + + return 0; + +out_of_memory: + list_for_each_entry_safe(rg, trg, &allocated_regions, link) { + list_del(&rg->link); + kfree(rg); + } + return -ENOMEM; +} + +/* + * Add the huge page range represented by [f, t) to the reserve + * map. Regions will be taken from the cache to fill in this range. + * Sufficient regions should exist in the cache due to the previous + * call to region_chg with the same range, but in some cases the cache will not + * have sufficient entries due to races with other code doing region_add or + * region_del. The extra needed entries will be allocated. + * + * regions_needed is the out value provided by a previous call to region_chg. + * + * Return the number of new huge pages added to the map. This number is greater + * than or equal to zero. If file_region entries needed to be allocated for + * this operation and we were not able to allocate, it returns -ENOMEM. + * region_add of regions of length 1 never allocate file_regions and cannot + * fail; region_chg will always allocate at least 1 entry and a region_add for + * 1 page will only require at most 1 entry. + */ +static long region_add(struct resv_map *resv, long f, long t, + long in_regions_needed, struct hstate *h, + struct hugetlb_cgroup *h_cg) +{ + long add = 0, actual_regions_needed = 0; + + spin_lock(&resv->lock); +retry: + + /* Count how many regions are actually needed to execute this add. */ + add_reservation_in_range(resv, f, t, NULL, NULL, + &actual_regions_needed); + + /* + * Check for sufficient descriptors in the cache to accommodate + * this add operation. Note that actual_regions_needed may be greater + * than in_regions_needed, as the resv_map may have been modified since + * the region_chg call. In this case, we need to make sure that we + * allocate extra entries, such that we have enough for all the + * existing adds_in_progress, plus the excess needed for this + * operation. + */ + if (actual_regions_needed > in_regions_needed && + resv->region_cache_count < + resv->adds_in_progress + + (actual_regions_needed - in_regions_needed)) { + /* region_add operation of range 1 should never need to + * allocate file_region entries. + */ + VM_BUG_ON(t - f <= 1); + + if (allocate_file_region_entries( + resv, actual_regions_needed - in_regions_needed)) { + return -ENOMEM; + } + + goto retry; + } + + add = add_reservation_in_range(resv, f, t, h_cg, h, NULL); + + resv->adds_in_progress -= in_regions_needed; + + spin_unlock(&resv->lock); + VM_BUG_ON(add < 0); + return add; +} + +/* + * Examine the existing reserve map and determine how many + * huge pages in the specified range [f, t) are NOT currently + * represented. This routine is called before a subsequent + * call to region_add that will actually modify the reserve + * map to add the specified range [f, t). region_chg does + * not change the number of huge pages represented by the + * map. A number of new file_region structures is added to the cache as a + * placeholder, for the subsequent region_add call to use. At least 1 + * file_region structure is added. + * + * out_regions_needed is the number of regions added to the + * resv->adds_in_progress. This value needs to be provided to a follow up call + * to region_add or region_abort for proper accounting. + * + * Returns the number of huge pages that need to be added to the existing + * reservation map for the range [f, t). This number is greater or equal to + * zero. -ENOMEM is returned if a new file_region structure or cache entry + * is needed and can not be allocated. + */ +static long region_chg(struct resv_map *resv, long f, long t, + long *out_regions_needed) +{ + long chg = 0; + + spin_lock(&resv->lock); + + /* Count how many hugepages in this range are NOT represented. */ + chg = add_reservation_in_range(resv, f, t, NULL, NULL, + out_regions_needed); + + if (*out_regions_needed == 0) + *out_regions_needed = 1; + + if (allocate_file_region_entries(resv, *out_regions_needed)) + return -ENOMEM; + + resv->adds_in_progress += *out_regions_needed; + + spin_unlock(&resv->lock); + return chg; +} + +/* + * Abort the in progress add operation. The adds_in_progress field + * of the resv_map keeps track of the operations in progress between + * calls to region_chg and region_add. Operations are sometimes + * aborted after the call to region_chg. In such cases, region_abort + * is called to decrement the adds_in_progress counter. regions_needed + * is the value returned by the region_chg call, it is used to decrement + * the adds_in_progress counter. + * + * NOTE: The range arguments [f, t) are not needed or used in this + * routine. They are kept to make reading the calling code easier as + * arguments will match the associated region_chg call. + */ +static void region_abort(struct resv_map *resv, long f, long t, + long regions_needed) +{ + spin_lock(&resv->lock); + VM_BUG_ON(!resv->region_cache_count); + resv->adds_in_progress -= regions_needed; + spin_unlock(&resv->lock); +} + +/* + * Delete the specified range [f, t) from the reserve map. If the + * t parameter is LONG_MAX, this indicates that ALL regions after f + * should be deleted. Locate the regions which intersect [f, t) + * and either trim, delete or split the existing regions. + * + * Returns the number of huge pages deleted from the reserve map. + * In the normal case, the return value is zero or more. In the + * case where a region must be split, a new region descriptor must + * be allocated. If the allocation fails, -ENOMEM will be returned. + * NOTE: If the parameter t == LONG_MAX, then we will never split + * a region and possibly return -ENOMEM. Callers specifying + * t == LONG_MAX do not need to check for -ENOMEM error. + */ +static long region_del(struct resv_map *resv, long f, long t) +{ + struct list_head *head = &resv->regions; + struct file_region *rg, *trg; + struct file_region *nrg = NULL; + long del = 0; + +retry: + spin_lock(&resv->lock); + list_for_each_entry_safe(rg, trg, head, link) { + /* + * Skip regions before the range to be deleted. file_region + * ranges are normally of the form [from, to). However, there + * may be a "placeholder" entry in the map which is of the form + * (from, to) with from == to. Check for placeholder entries + * at the beginning of the range to be deleted. + */ + if (rg->to <= f && (rg->to != rg->from || rg->to != f)) + continue; + + if (rg->from >= t) + break; + + if (f > rg->from && t < rg->to) { /* Must split region */ + /* + * Check for an entry in the cache before dropping + * lock and attempting allocation. + */ + if (!nrg && + resv->region_cache_count > resv->adds_in_progress) { + nrg = list_first_entry(&resv->region_cache, + struct file_region, + link); + list_del(&nrg->link); + resv->region_cache_count--; + } + + if (!nrg) { + spin_unlock(&resv->lock); + nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); + if (!nrg) + return -ENOMEM; + goto retry; + } + + del += t - f; + hugetlb_cgroup_uncharge_file_region( + resv, rg, t - f, false); + + /* New entry for end of split region */ + nrg->from = t; + nrg->to = rg->to; + + copy_hugetlb_cgroup_uncharge_info(nrg, rg); + + INIT_LIST_HEAD(&nrg->link); + + /* Original entry is trimmed */ + rg->to = f; + + list_add(&nrg->link, &rg->link); + nrg = NULL; + break; + } + + if (f <= rg->from && t >= rg->to) { /* Remove entire region */ + del += rg->to - rg->from; + hugetlb_cgroup_uncharge_file_region(resv, rg, + rg->to - rg->from, true); + list_del(&rg->link); + kfree(rg); + continue; + } + + if (f <= rg->from) { /* Trim beginning of region */ + hugetlb_cgroup_uncharge_file_region(resv, rg, + t - rg->from, false); + + del += t - rg->from; + rg->from = t; + } else { /* Trim end of region */ + hugetlb_cgroup_uncharge_file_region(resv, rg, + rg->to - f, false); + + del += rg->to - f; + rg->to = f; + } + } + + spin_unlock(&resv->lock); + kfree(nrg); + return del; +} + +/* + * A rare out of memory error was encountered which prevented removal of + * the reserve map region for a page. The huge page itself was free'ed + * and removed from the page cache. This routine will adjust the subpool + * usage count, and the global reserve count if needed. By incrementing + * these counts, the reserve map entry which could not be deleted will + * appear as a "reserved" entry instead of simply dangling with incorrect + * counts. + */ +void hugetlb_fix_reserve_counts(struct inode *inode) +{ + struct hugepage_subpool *spool = subpool_inode(inode); + long rsv_adjust; + bool reserved = false; + + rsv_adjust = hugepage_subpool_get_pages(spool, 1); + if (rsv_adjust > 0) { + struct hstate *h = hstate_inode(inode); + + if (!hugetlb_acct_memory(h, 1)) + reserved = true; + } else if (!rsv_adjust) { + reserved = true; + } + + if (!reserved) + pr_warn("hugetlb: Huge Page Reserved count may go negative.\n"); +} + +/* + * Count and return the number of huge pages in the reserve map + * that intersect with the range [f, t). + */ +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); +} +EXPORT_SYMBOL_GPL(linear_hugepage_index); + +/* + * 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) +{ + if (vma->vm_ops && vma->vm_ops->pagesize) + return vma->vm_ops->pagesize(vma); + return PAGE_SIZE; +} +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 'strong' + * version of this symbol is required. + */ +__weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) +{ + return vma_kernel_pagesize(vma); +} + +/* + * 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; +} + +static void +resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map, + struct hugetlb_cgroup *h_cg, + struct hstate *h) +{ +#ifdef CONFIG_CGROUP_HUGETLB + if (!h_cg || !h) { + resv_map->reservation_counter = NULL; + resv_map->pages_per_hpage = 0; + resv_map->css = NULL; + } else { + resv_map->reservation_counter = + &h_cg->rsvd_hugepage[hstate_index(h)]; + resv_map->pages_per_hpage = pages_per_huge_page(h); + resv_map->css = &h_cg->css; + } +#endif +} + +struct resv_map *resv_map_alloc(void) +{ + struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); + struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL); + + if (!resv_map || !rg) { + kfree(resv_map); + kfree(rg); + return NULL; + } + + kref_init(&resv_map->refs); + spin_lock_init(&resv_map->lock); + INIT_LIST_HEAD(&resv_map->regions); + + resv_map->adds_in_progress = 0; + /* + * Initialize these to 0. On shared mappings, 0's here indicate these + * fields don't do cgroup accounting. On private mappings, these will be + * re-initialized to the proper values, to indicate that hugetlb cgroup + * reservations are to be un-charged from here. + */ + resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL); + + INIT_LIST_HEAD(&resv_map->region_cache); + list_add(&rg->link, &resv_map->region_cache); + resv_map->region_cache_count = 1; + + return resv_map; +} + +void resv_map_release(struct kref *ref) +{ + struct resv_map *resv_map = container_of(ref, struct resv_map, refs); + struct list_head *head = &resv_map->region_cache; + struct file_region *rg, *trg; + + /* Clear out any active regions before we release the map. */ + region_del(resv_map, 0, LONG_MAX); + + /* ... and any entries left in the cache */ + list_for_each_entry_safe(rg, trg, head, link) { + list_del(&rg->link); + kfree(rg); + } + + VM_BUG_ON(resv_map->adds_in_progress); + + kfree(resv_map); +} + +static inline struct resv_map *inode_resv_map(struct inode *inode) +{ + /* + * At inode evict time, i_mapping may not point to the original + * address space within the inode. This original address space + * contains the pointer to the resv_map. So, always use the + * address space embedded within the inode. + * The VERY common case is inode->mapping == &inode->i_data but, + * this may not be true for device special inodes. + */ + return (struct resv_map *)(&inode->i_data)->private_data; +} + +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 bool 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 true; + else + return false; + } + + /* Shared mappings always use reserves */ + if (vma->vm_flags & VM_MAYSHARE) { + /* + * We know VM_NORESERVE is not set. Therefore, there SHOULD + * be a region map for all pages. The only situation where + * there is no region map is if a hole was punched via + * fallocate. In this case, there really are no reserves to + * use. This situation is indicated if chg != 0. + */ + if (chg) + return false; + else + return true; + } + + /* + * Only the process that called mmap() has reserves for + * private mappings. + */ + if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { + /* + * Like the shared case above, a hole punch or truncate + * could have been performed on the private mapping. + * Examine the value of chg to determine if reserves + * actually exist or were previously consumed. + * Very Subtle - The value of chg comes from a previous + * call to vma_needs_reserves(). The reserve map for + * private mappings has different (opposite) semantics + * than that of shared mappings. vma_needs_reserves() + * has already taken this difference in semantics into + * account. Therefore, the meaning of chg is the same + * as in the shared case above. Code could easily be + * combined, but keeping it separate draws attention to + * subtle differences. + */ + if (chg) + return false; + else + return true; + } + + return false; +} + +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]++; + SetPageHugeFreed(page); +} + +static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid) +{ + struct page *page; + bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA); + + list_for_each_entry(page, &h->hugepage_freelists[nid], lru) { + if (nocma && is_migrate_cma_page(page)) + continue; + + if (PageHWPoison(page)) + continue; + + list_move(&page->lru, &h->hugepage_activelist); + set_page_refcounted(page); + ClearPageHugeFreed(page); + h->free_huge_pages--; + h->free_huge_pages_node[nid]--; + return page; + } + + return NULL; +} + +static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid, + nodemask_t *nmask) +{ + unsigned int cpuset_mems_cookie; + struct zonelist *zonelist; + struct zone *zone; + struct zoneref *z; + int node = NUMA_NO_NODE; + + zonelist = node_zonelist(nid, gfp_mask); + +retry_cpuset: + cpuset_mems_cookie = read_mems_allowed_begin(); + for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) { + struct page *page; + + if (!cpuset_zone_allowed(zone, gfp_mask)) + continue; + /* + * no need to ask again on the same node. Pool is node rather than + * zone aware + */ + if (zone_to_nid(zone) == node) + continue; + node = zone_to_nid(zone); + + page = dequeue_huge_page_node_exact(h, node); + if (page) + return page; + } + if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie))) + goto retry_cpuset; + + return NULL; +} + +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; + struct mempolicy *mpol; + gfp_t gfp_mask; + nodemask_t *nodemask; + int nid; + + /* + * 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; + + gfp_mask = htlb_alloc_mask(h); + nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask); + page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); + if (page && !avoid_reserve && vma_has_reserves(vma, chg)) { + SetPagePrivate(page); + h->resv_huge_pages--; + } + + mpol_cond_put(mpol); + 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_in(nid, *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--) + +#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE +static void destroy_compound_gigantic_page(struct page *page, + unsigned int order) +{ + int i; + int nr_pages = 1 << order; + struct page *p = page + 1; + + atomic_set(compound_mapcount_ptr(page), 0); + atomic_set(compound_pincount_ptr(page), 0); + + for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { + clear_compound_head(p); + set_page_refcounted(p); + } + + set_compound_order(page, 0); + page[1].compound_nr = 0; + __ClearPageHead(page); +} + +static void free_gigantic_page(struct page *page, unsigned int order) +{ + /* + * If the page isn't allocated using the cma allocator, + * cma_release() returns false. + */ +#ifdef CONFIG_CMA + if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order)) + return; +#endif + + free_contig_range(page_to_pfn(page), 1 << order); +} + +#ifdef CONFIG_CONTIG_ALLOC +static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, + int nid, nodemask_t *nodemask) +{ + unsigned long nr_pages = 1UL << huge_page_order(h); + if (nid == NUMA_NO_NODE) + nid = numa_mem_id(); + +#ifdef CONFIG_CMA + { + struct page *page; + int node; + + if (hugetlb_cma[nid]) { + page = cma_alloc(hugetlb_cma[nid], nr_pages, + huge_page_order(h), true); + if (page) + return page; + } + + if (!(gfp_mask & __GFP_THISNODE)) { + for_each_node_mask(node, *nodemask) { + if (node == nid || !hugetlb_cma[node]) + continue; + + page = cma_alloc(hugetlb_cma[node], nr_pages, + huge_page_order(h), true); + if (page) + return page; + } + } + } +#endif + + return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask); +} + +#else /* !CONFIG_CONTIG_ALLOC */ +static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, + int nid, nodemask_t *nodemask) +{ + return NULL; +} +#endif /* CONFIG_CONTIG_ALLOC */ + +#else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */ +static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask, + int nid, nodemask_t *nodemask) +{ + return NULL; +} +static inline void free_gigantic_page(struct page *page, unsigned int order) { } +static inline void destroy_compound_gigantic_page(struct page *page, + unsigned int order) { } +#endif + +static void update_and_free_page(struct hstate *h, struct page *page) +{ + int i; + struct page *subpage = page; + + if (hstate_is_gigantic(h) && !gigantic_page_runtime_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++, subpage = mem_map_next(subpage, page, i)) { + subpage->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); + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page); + set_compound_page_dtor(page, NULL_COMPOUND_DTOR); + set_page_refcounted(page); + if (hstate_is_gigantic(h)) { + /* + * Temporarily drop the hugetlb_lock, because + * we might block in free_gigantic_page(). + */ + spin_unlock(&hugetlb_lock); + destroy_compound_gigantic_page(page, huge_page_order(h)); + free_gigantic_page(page, huge_page_order(h)); + spin_lock(&hugetlb_lock); + } else { + __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) +{ + return PageHeadHuge(page) && PagePrivate(&page[1]); +} + +/* never called for tail page */ +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]); +} + +/* + * Internal hugetlb specific page flag. Do not use outside of the hugetlb + * code + */ +static inline bool PageHugeTemporary(struct page *page) +{ + if (!PageHuge(page)) + return false; + + return (unsigned long)page[2].mapping == -1U; +} + +static inline void SetPageHugeTemporary(struct page *page) +{ + page[2].mapping = (void *)-1U; +} + +static inline void ClearPageHugeTemporary(struct page *page) +{ + page[2].mapping = NULL; +} + +static void __free_huge_page(struct page *page) +{ + /* + * Can't pass hstate in here because it is called from the + * compound page destructor. + */ + struct hstate *h = page_hstate(page); + int nid = page_to_nid(page); + struct hugepage_subpool *spool = + (struct hugepage_subpool *)page_private(page); + bool restore_reserve; + + VM_BUG_ON_PAGE(page_count(page), page); + VM_BUG_ON_PAGE(page_mapcount(page), page); + + set_page_private(page, 0); + page->mapping = NULL; + restore_reserve = PagePrivate(page); + ClearPagePrivate(page); + + /* + * If PagePrivate() was set on page, page allocation consumed a + * reservation. If the page was associated with a subpool, there + * would have been a page reserved in the subpool before allocation + * via hugepage_subpool_get_pages(). Since we are 'restoring' the + * reservtion, do not call hugepage_subpool_put_pages() as this will + * remove the reserved page from the subpool. + */ + if (!restore_reserve) { + /* + * A return code of zero implies that the subpool will be + * under its minimum size if the reservation is not restored + * after page is free. Therefore, force restore_reserve + * operation. + */ + if (hugepage_subpool_put_pages(spool, 1) == 0) + restore_reserve = true; + } + + spin_lock(&hugetlb_lock); + clear_page_huge_active(page); + hugetlb_cgroup_uncharge_page(hstate_index(h), + pages_per_huge_page(h), page); + hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h), + pages_per_huge_page(h), page); + if (restore_reserve) + h->resv_huge_pages++; + + if (PageHugeTemporary(page)) { + list_del(&page->lru); + ClearPageHugeTemporary(page); + update_and_free_page(h, page); + } else 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); +} + +/* + * As free_huge_page() can be called from a non-task context, we have + * to defer the actual freeing in a workqueue to prevent potential + * hugetlb_lock deadlock. + * + * free_hpage_workfn() locklessly retrieves the linked list of pages to + * be freed and frees them one-by-one. As the page->mapping pointer is + * going to be cleared in __free_huge_page() anyway, it is reused as the + * llist_node structure of a lockless linked list of huge pages to be freed. + */ +static LLIST_HEAD(hpage_freelist); + +static void free_hpage_workfn(struct work_struct *work) +{ + struct llist_node *node; + struct page *page; + + node = llist_del_all(&hpage_freelist); + + while (node) { + page = container_of((struct address_space **)node, + struct page, mapping); + node = node->next; + __free_huge_page(page); + } +} +static DECLARE_WORK(free_hpage_work, free_hpage_workfn); + +void free_huge_page(struct page *page) +{ + /* + * Defer freeing if in non-task context to avoid hugetlb_lock deadlock. + */ + if (!in_task()) { + /* + * Only call schedule_work() if hpage_freelist is previously + * empty. Otherwise, schedule_work() had been called but the + * workfn hasn't retrieved the list yet. + */ + if (llist_add((struct llist_node *)&page->mapping, + &hpage_freelist)) + schedule_work(&free_hpage_work); + return; + } + + __free_huge_page(page); +} + +static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) +{ + INIT_LIST_HEAD(&page->lru); + set_compound_page_dtor(page, HUGETLB_PAGE_DTOR); + set_hugetlb_cgroup(page, NULL); + set_hugetlb_cgroup_rsvd(page, NULL); + spin_lock(&hugetlb_lock); + h->nr_huge_pages++; + h->nr_huge_pages_node[nid]++; + ClearPageHugeFreed(page); + spin_unlock(&hugetlb_lock); +} + +static void prep_compound_gigantic_page(struct page *page, unsigned int 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); + __ClearPageReserved(page); + __SetPageHead(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. Otherwise 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); + set_compound_head(p, page); + } + atomic_set(compound_mapcount_ptr(page), -1); + atomic_set(compound_pincount_ptr(page), 0); +} + +/* + * 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 page[1].compound_dtor == HUGETLB_PAGE_DTOR; +} +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 page_head[1].compound_dtor == HUGETLB_PAGE_DTOR; +} + +/* + * Find and lock address space (mapping) in write mode. + * + * Upon entry, the page is locked which means that page_mapping() is + * stable. Due to locking order, we can only trylock_write. If we can + * not get the lock, simply return NULL to caller. + */ +struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage) +{ + struct address_space *mapping = page_mapping(hpage); + + if (!mapping) + return mapping; + + if (i_mmap_trylock_write(mapping)) + return mapping; + + return NULL; +} + +pgoff_t hugetlb_basepage_index(struct page *page) +{ + struct page *page_head = compound_head(page); + pgoff_t index = page_index(page_head); + unsigned long compound_idx; + + 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_buddy_huge_page(struct hstate *h, + gfp_t gfp_mask, int nid, nodemask_t *nmask, + nodemask_t *node_alloc_noretry) +{ + int order = huge_page_order(h); + struct page *page; + bool alloc_try_hard = true; + + /* + * By default we always try hard to allocate the page with + * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in + * a loop (to adjust global huge page counts) and previous allocation + * failed, do not continue to try hard on the same node. Use the + * node_alloc_noretry bitmap to manage this state information. + */ + if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry)) + alloc_try_hard = false; + gfp_mask |= __GFP_COMP|__GFP_NOWARN; + if (alloc_try_hard) + gfp_mask |= __GFP_RETRY_MAYFAIL; + if (nid == NUMA_NO_NODE) + nid = numa_mem_id(); + page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask); + if (page) + __count_vm_event(HTLB_BUDDY_PGALLOC); + else + __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); + + /* + * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this + * indicates an overall state change. Clear bit so that we resume + * normal 'try hard' allocations. + */ + if (node_alloc_noretry && page && !alloc_try_hard) + node_clear(nid, *node_alloc_noretry); + + /* + * If we tried hard to get a page but failed, set bit so that + * subsequent attempts will not try as hard until there is an + * overall state change. + */ + if (node_alloc_noretry && !page && alloc_try_hard) + node_set(nid, *node_alloc_noretry); + + return page; +} + +/* + * Common helper to allocate a fresh hugetlb page. All specific allocators + * should use this function to get new hugetlb pages + */ +static struct page *alloc_fresh_huge_page(struct hstate *h, + gfp_t gfp_mask, int nid, nodemask_t *nmask, + nodemask_t *node_alloc_noretry) +{ + struct page *page; + + if (hstate_is_gigantic(h)) + page = alloc_gigantic_page(h, gfp_mask, nid, nmask); + else + page = alloc_buddy_huge_page(h, gfp_mask, + nid, nmask, node_alloc_noretry); + if (!page) + return NULL; + + if (hstate_is_gigantic(h)) + prep_compound_gigantic_page(page, huge_page_order(h)); + prep_new_huge_page(h, page, page_to_nid(page)); + + return page; +} + +/* + * Allocates a fresh page to the hugetlb allocator pool in the node interleaved + * manner. + */ +static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, + nodemask_t *node_alloc_noretry) +{ + struct page *page; + int nr_nodes, node; + gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; + + for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { + page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed, + node_alloc_noretry); + if (page) + break; + } + + if (!page) + return 0; + + put_page(page); /* free it into the hugepage allocator */ + + return 1; +} + +/* + * 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 hugepages and non-hugepages. + * This function returns values like below: + * + * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use + * (allocated or reserved.) + * 0: successfully dissolved free hugepages or the page is not a + * hugepage (considered as already dissolved) + */ +int dissolve_free_huge_page(struct page *page) +{ + int rc = -EBUSY; + +retry: + /* Not to disrupt normal path by vainly holding hugetlb_lock */ + if (!PageHuge(page)) + return 0; + + spin_lock(&hugetlb_lock); + if (!PageHuge(page)) { + rc = 0; + goto out; + } + + if (!page_count(page)) { + struct page *head = compound_head(page); + struct hstate *h = page_hstate(head); + int nid = page_to_nid(head); + if (h->free_huge_pages - h->resv_huge_pages == 0) + goto out; + + /* + * We should make sure that the page is already on the free list + * when it is dissolved. + */ + if (unlikely(!PageHugeFreed(head))) { + spin_unlock(&hugetlb_lock); + cond_resched(); + + /* + * Theoretically, we should return -EBUSY when we + * encounter this race. In fact, we have a chance + * to successfully dissolve the page if we do a + * retry. Because the race window is quite small. + * If we seize this opportunity, it is an optimization + * for increasing the success rate of dissolving page. + */ + goto retry; + } + + /* + * Move PageHWPoison flag from head page to the raw error page, + * which makes any subpages rather than the error page reusable. + */ + if (PageHWPoison(head) && page != head) { + SetPageHWPoison(page); + ClearPageHWPoison(head); + } + list_del(&head->lru); + h->free_huge_pages--; + h->free_huge_pages_node[nid]--; + h->max_huge_pages--; + update_and_free_page(h, head); + rc = 0; + } +out: + spin_unlock(&hugetlb_lock); + return rc; +} + +/* + * Dissolve free hugepages in a given pfn range. Used by memory hotplug to + * make specified memory blocks removable from the system. + * Note that this will dissolve a free gigantic hugepage completely, if any + * part of it lies within the given range. + * Also note that if dissolve_free_huge_page() returns with an error, all + * free hugepages that were dissolved before that error are lost. + */ +int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) +{ + unsigned long pfn; + struct page *page; + int rc = 0; + + if (!hugepages_supported()) + return rc; + + for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) { + page = pfn_to_page(pfn); + rc = dissolve_free_huge_page(page); + if (rc) + break; + } + + return rc; +} + +/* + * Allocates a fresh surplus page from the page allocator. + */ +static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask, + int nid, nodemask_t *nmask) +{ + struct page *page = NULL; + + if (hstate_is_gigantic(h)) + return NULL; + + spin_lock(&hugetlb_lock); + if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) + goto out_unlock; + spin_unlock(&hugetlb_lock); + + page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL); + if (!page) + return NULL; + + spin_lock(&hugetlb_lock); + /* + * We could have raced with the pool size change. + * Double check that and simply deallocate the new page + * if we would end up overcommiting the surpluses. Abuse + * temporary page to workaround the nasty free_huge_page + * codeflow + */ + if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { + SetPageHugeTemporary(page); + spin_unlock(&hugetlb_lock); + put_page(page); + return NULL; + } else { + h->surplus_huge_pages++; + h->surplus_huge_pages_node[page_to_nid(page)]++; + } + +out_unlock: + spin_unlock(&hugetlb_lock); + + return page; +} + +static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask, + int nid, nodemask_t *nmask) +{ + struct page *page; + + if (hstate_is_gigantic(h)) + return NULL; + + page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL); + if (!page) + return NULL; + + /* + * We do not account these pages as surplus because they are only + * temporary and will be released properly on the last reference + */ + SetPageHugeTemporary(page); + + return page; +} + +/* + * Use the VMA's mpolicy to allocate a huge page from the buddy. + */ +static +struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr) +{ + struct page *page; + struct mempolicy *mpol; + gfp_t gfp_mask = htlb_alloc_mask(h); + int nid; + nodemask_t *nodemask; + + nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask); + page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask); + mpol_cond_put(mpol); + + return page; +} + +/* page migration callback function */ +struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid, + nodemask_t *nmask, gfp_t gfp_mask) +{ + spin_lock(&hugetlb_lock); + if (h->free_huge_pages - h->resv_huge_pages > 0) { + struct page *page; + + page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask); + if (page) { + spin_unlock(&hugetlb_lock); + return page; + } + } + spin_unlock(&hugetlb_lock); + + return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask); +} + +/* mempolicy aware migration callback */ +struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma, + unsigned long address) +{ + struct mempolicy *mpol; + nodemask_t *nodemask; + struct page *page; + gfp_t gfp_mask; + int node; + + gfp_mask = htlb_alloc_mask(h); + node = huge_node(vma, address, gfp_mask, &mpol, &nodemask); + page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask); + mpol_cond_put(mpol); + + 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) + __must_hold(&hugetlb_lock) +{ + 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_surplus_huge_page(h, htlb_alloc_mask(h), + NUMA_NO_NODE, NULL); + if (!page) { + alloc_ok = false; + break; + } + list_add(&page->lru, &surplus_list); + cond_resched(); + } + 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; +} + +/* + * This routine has two main purposes: + * 1) Decrement the reservation count (resv_huge_pages) by the value passed + * in unused_resv_pages. This corresponds to the prior adjustments made + * to the associated reservation map. + * 2) Free any unused surplus pages that may have been allocated to satisfy + * the reservation. As many as unused_resv_pages may be freed. + * + * Called with hugetlb_lock held. However, the lock could be dropped (and + * reacquired) during calls to cond_resched_lock. Whenever dropping the lock, + * we must make sure nobody else can claim pages we are in the process of + * freeing. Do this by ensuring resv_huge_page always is greater than the + * number of huge pages we plan to free when dropping the lock. + */ +static void return_unused_surplus_pages(struct hstate *h, + unsigned long unused_resv_pages) +{ + unsigned long nr_pages; + + /* Cannot return gigantic pages currently */ + if (hstate_is_gigantic(h)) + goto out; + + /* + * Part (or even all) of the reservation could have been backed + * by pre-allocated pages. Only free surplus pages. + */ + 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 freed pages across the + * on-line nodes with memory and will handle the hstate accounting. + * + * Note that we decrement resv_huge_pages as we free the pages. If + * we drop the lock, resv_huge_pages will still be sufficiently large + * to cover subsequent pages we may free. + */ + while (nr_pages--) { + h->resv_huge_pages--; + unused_resv_pages--; + if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) + goto out; + cond_resched_lock(&hugetlb_lock); + } + +out: + /* Fully uncommit the reservation */ + h->resv_huge_pages -= unused_resv_pages; +} + + +/* + * vma_needs_reservation, vma_commit_reservation and vma_end_reservation + * are used by the huge page allocation routines to manage reservations. + * + * vma_needs_reservation is called to determine if the huge page at addr + * within the vma has an associated reservation. If a reservation is + * needed, the value 1 is returned. The caller is then responsible for + * managing the global reservation and subpool usage counts. After + * the huge page has been allocated, vma_commit_reservation is called + * to add the page to the reservation map. If the page allocation fails, + * the reservation must be ended instead of committed. vma_end_reservation + * is called in such cases. + * + * In the normal case, vma_commit_reservation returns the same value + * as the preceding vma_needs_reservation call. The only time this + * is not the case is if a reserve map was changed between calls. It + * is the responsibility of the caller to notice the difference and + * take appropriate action. + * + * vma_add_reservation is used in error paths where a reservation must + * be restored when a newly allocated huge page must be freed. It is + * to be called after calling vma_needs_reservation to determine if a + * reservation exists. + */ +enum vma_resv_mode { + VMA_NEEDS_RESV, + VMA_COMMIT_RESV, + VMA_END_RESV, + VMA_ADD_RESV, +}; +static long __vma_reservation_common(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr, + enum vma_resv_mode mode) +{ + struct resv_map *resv; + pgoff_t idx; + long ret; + long dummy_out_regions_needed; + + resv = vma_resv_map(vma); + if (!resv) + return 1; + + idx = vma_hugecache_offset(h, vma, addr); + switch (mode) { + case VMA_NEEDS_RESV: + ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed); + /* We assume that vma_reservation_* routines always operate on + * 1 page, and that adding to resv map a 1 page entry can only + * ever require 1 region. + */ + VM_BUG_ON(dummy_out_regions_needed != 1); + break; + case VMA_COMMIT_RESV: + ret = region_add(resv, idx, idx + 1, 1, NULL, NULL); + /* region_add calls of range 1 should never fail. */ + VM_BUG_ON(ret < 0); + break; + case VMA_END_RESV: + region_abort(resv, idx, idx + 1, 1); + ret = 0; + break; + case VMA_ADD_RESV: + if (vma->vm_flags & VM_MAYSHARE) { + ret = region_add(resv, idx, idx + 1, 1, NULL, NULL); + /* region_add calls of range 1 should never fail. */ + VM_BUG_ON(ret < 0); + } else { + region_abort(resv, idx, idx + 1, 1); + ret = region_del(resv, idx, idx + 1); + } + break; + default: + BUG(); + } + + if (vma->vm_flags & VM_MAYSHARE) + return ret; + else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) { + /* + * In most cases, reserves always exist for private mappings. + * However, a file associated with mapping could have been + * hole punched or truncated after reserves were consumed. + * As subsequent fault on such a range will not use reserves. + * Subtle - The reserve map for private mappings has the + * opposite meaning than that of shared mappings. If NO + * entry is in the reserve map, it means a reservation exists. + * If an entry exists in the reserve map, it means the + * reservation has already been consumed. As a result, the + * return value of this routine is the opposite of the + * value returned from reserve map manipulation routines above. + */ + if (ret) + return 0; + else + return 1; + } + else + return ret < 0 ? ret : 0; +} + +static long vma_needs_reservation(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr) +{ + return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV); +} + +static long vma_commit_reservation(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr) +{ + return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV); +} + +static void vma_end_reservation(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr) +{ + (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV); +} + +static long vma_add_reservation(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr) +{ + return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV); +} + +/* + * This routine is called to restore a reservation on error paths. In the + * specific error paths, a huge page was allocated (via alloc_huge_page) + * and is about to be freed. If a reservation for the page existed, + * alloc_huge_page would have consumed the reservation and set PagePrivate + * in the newly allocated page. When the page is freed via free_huge_page, + * the global reservation count will be incremented if PagePrivate is set. + * However, free_huge_page can not adjust the reserve map. Adjust the + * reserve map here to be consistent with global reserve count adjustments + * to be made by free_huge_page. + */ +static void restore_reserve_on_error(struct hstate *h, + struct vm_area_struct *vma, unsigned long address, + struct page *page) +{ + if (unlikely(PagePrivate(page))) { + long rc = vma_needs_reservation(h, vma, address); + + if (unlikely(rc < 0)) { + /* + * Rare out of memory condition in reserve map + * manipulation. Clear PagePrivate so that + * global reserve count will not be incremented + * by free_huge_page. This will make it appear + * as though the reservation for this page was + * consumed. This may prevent the task from + * faulting in the page at a later time. This + * is better than inconsistent global huge page + * accounting of reserve counts. + */ + ClearPagePrivate(page); + } else if (rc) { + rc = vma_add_reservation(h, vma, address); + if (unlikely(rc < 0)) + /* + * See above comment about rare out of + * memory condition. + */ + ClearPagePrivate(page); + } else + vma_end_reservation(h, vma, address); + } +} + +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 map_chg, map_commit; + long gbl_chg; + int ret, idx; + struct hugetlb_cgroup *h_cg; + bool deferred_reserve; + + idx = hstate_index(h); + /* + * Examine the region/reserve map to determine if the process + * has a reservation for the page to be allocated. A return + * code of zero indicates a reservation exists (no change). + */ + map_chg = gbl_chg = vma_needs_reservation(h, vma, addr); + if (map_chg < 0) + return ERR_PTR(-ENOMEM); + + /* + * Processes that did not create the mapping will have no + * reserves as indicated by the region/reserve map. Check + * that the allocation will not exceed the subpool limit. + * Allocations for MAP_NORESERVE mappings also need to be + * checked against any subpool limit. + */ + if (map_chg || avoid_reserve) { + gbl_chg = hugepage_subpool_get_pages(spool, 1); + if (gbl_chg < 0) { + vma_end_reservation(h, vma, addr); + return ERR_PTR(-ENOSPC); + } + + /* + * Even though there was no reservation in the region/reserve + * map, there could be reservations associated with the + * subpool that can be used. This would be indicated if the + * return value of hugepage_subpool_get_pages() is zero. + * However, if avoid_reserve is specified we still avoid even + * the subpool reservations. + */ + if (avoid_reserve) + gbl_chg = 1; + } + + /* If this allocation is not consuming a reservation, charge it now. + */ + deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma); + if (deferred_reserve) { + ret = hugetlb_cgroup_charge_cgroup_rsvd( + idx, pages_per_huge_page(h), &h_cg); + if (ret) + goto out_subpool_put; + } + + ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); + if (ret) + goto out_uncharge_cgroup_reservation; + + spin_lock(&hugetlb_lock); + /* + * glb_chg is passed to indicate whether or not a page must be taken + * from the global free pool (global change). gbl_chg == 0 indicates + * a reservation exists for the allocation. + */ + page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg); + if (!page) { + spin_unlock(&hugetlb_lock); + page = alloc_buddy_huge_page_with_mpol(h, vma, addr); + if (!page) + goto out_uncharge_cgroup; + spin_lock(&hugetlb_lock); + if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { + SetPagePrivate(page); + h->resv_huge_pages--; + } + list_add(&page->lru, &h->hugepage_activelist); + /* Fall through */ + } + hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); + /* If allocation is not consuming a reservation, also store the + * hugetlb_cgroup pointer on the page. + */ + if (deferred_reserve) { + hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h), + h_cg, page); + } + + spin_unlock(&hugetlb_lock); + + set_page_private(page, (unsigned long)spool); + + map_commit = vma_commit_reservation(h, vma, addr); + if (unlikely(map_chg > map_commit)) { + /* + * The page was added to the reservation map between + * vma_needs_reservation and vma_commit_reservation. + * This indicates a race with hugetlb_reserve_pages. + * Adjust for the subpool count incremented above AND + * in hugetlb_reserve_pages for the same page. Also, + * the reservation count added in hugetlb_reserve_pages + * no longer applies. + */ + long rsv_adjust; + + rsv_adjust = hugepage_subpool_put_pages(spool, 1); + hugetlb_acct_memory(h, -rsv_adjust); + if (deferred_reserve) + hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h), + pages_per_huge_page(h), page); + } + return page; + +out_uncharge_cgroup: + hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); +out_uncharge_cgroup_reservation: + if (deferred_reserve) + hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h), + h_cg); +out_subpool_put: + if (map_chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); + vma_end_reservation(h, vma, addr); + return ERR_PTR(-ENOSPC); +} + +int alloc_bootmem_huge_page(struct hstate *h) + __attribute__ ((weak, alias("__alloc_bootmem_huge_page"))); +int __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_alloc_try_nid_raw( + huge_page_size(h), huge_page_size(h), + 0, MEMBLOCK_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 */ + INIT_LIST_HEAD(&m->list); + list_add(&m->list, &huge_boot_pages); + m->hstate = h; + return 1; +} + +/* + * Put bootmem huge pages into the standard lists after mem_map is up. + * Note: This only applies to gigantic (order > MAX_ORDER) pages. + */ +static void __init gather_bootmem_prealloc(void) +{ + struct huge_bootmem_page *m; + + list_for_each_entry(m, &huge_boot_pages, list) { + struct page *page = virt_to_page(m); + struct hstate *h = m->hstate; + + VM_BUG_ON(!hstate_is_gigantic(h)); + WARN_ON(page_count(page) != 1); + prep_compound_gigantic_page(page, huge_page_order(h)); + WARN_ON(PageReserved(page)); + prep_new_huge_page(h, page, page_to_nid(page)); + put_page(page); /* free it into the hugepage allocator */ + + /* + * We need to restore the 'stolen' pages to totalram_pages + * in order to fix confusing memory reports from free(1) and + * other side-effects, like CommitLimit going negative. + */ + adjust_managed_page_count(page, pages_per_huge_page(h)); + cond_resched(); + } +} + +static void __init hugetlb_hstate_alloc_pages(struct hstate *h) +{ + unsigned long i; + nodemask_t *node_alloc_noretry; + + if (!hstate_is_gigantic(h)) { + /* + * Bit mask controlling how hard we retry per-node allocations. + * Ignore errors as lower level routines can deal with + * node_alloc_noretry == NULL. If this kmalloc fails at boot + * time, we are likely in bigger trouble. + */ + node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry), + GFP_KERNEL); + } else { + /* allocations done at boot time */ + node_alloc_noretry = NULL; + } + + /* bit mask controlling how hard we retry per-node allocations */ + if (node_alloc_noretry) + nodes_clear(*node_alloc_noretry); + + for (i = 0; i < h->max_huge_pages; ++i) { + if (hstate_is_gigantic(h)) { + if (hugetlb_cma_size) { + pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n"); + goto free; + } + if (!alloc_bootmem_huge_page(h)) + break; + } else if (!alloc_pool_huge_page(h, + &node_states[N_MEMORY], + node_alloc_noretry)) + break; + cond_resched(); + } + if (i < h->max_huge_pages) { + char buf[32]; + + string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); + pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n", + h->max_huge_pages, buf, i); + h->max_huge_pages = i; + } +free: + kfree(node_alloc_noretry); +} + +static void __init hugetlb_init_hstates(void) +{ + struct hstate *h; + + for_each_hstate(h) { + if (minimum_order > huge_page_order(h)) + minimum_order = huge_page_order(h); + + /* oversize hugepages were init'ed in early boot */ + if (!hstate_is_gigantic(h)) + hugetlb_hstate_alloc_pages(h); + } + VM_BUG_ON(minimum_order == UINT_MAX); +} + +static void __init report_hugepages(void) +{ + struct hstate *h; + + for_each_hstate(h) { + char buf[32]; + + string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); + pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", + buf, 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 int set_max_huge_pages(struct hstate *h, unsigned long count, int nid, + nodemask_t *nodes_allowed) +{ + unsigned long min_count, ret; + NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL); + + /* + * Bit mask controlling how hard we retry per-node allocations. + * If we can not allocate the bit mask, do not attempt to allocate + * the requested huge pages. + */ + if (node_alloc_noretry) + nodes_clear(*node_alloc_noretry); + else + return -ENOMEM; + + spin_lock(&hugetlb_lock); + + /* + * Check for a node specific request. + * Changing node specific huge page count may require a corresponding + * change to the global count. In any case, the passed node mask + * (nodes_allowed) will restrict alloc/free to the specified node. + */ + if (nid != NUMA_NO_NODE) { + unsigned long old_count = count; + + count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; + /* + * User may have specified a large count value which caused the + * above calculation to overflow. In this case, they wanted + * to allocate as many huge pages as possible. Set count to + * largest possible value to align with their intention. + */ + if (count < old_count) + count = ULONG_MAX; + } + + /* + * Gigantic pages runtime allocation depend on the capability for large + * page range allocation. + * If the system does not provide this feature, return an error when + * the user tries to allocate gigantic pages but let the user free the + * boottime allocated gigantic pages. + */ + if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) { + if (count > persistent_huge_pages(h)) { + spin_unlock(&hugetlb_lock); + NODEMASK_FREE(node_alloc_noretry); + return -EINVAL; + } + /* Fall through to decrease pool */ + } + + /* + * 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_surplus_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. + */ + 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); + + /* yield cpu to avoid soft lockup */ + cond_resched(); + + ret = alloc_pool_huge_page(h, nodes_allowed, + node_alloc_noretry); + 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_surplus_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: + h->max_huge_pages = persistent_huge_pages(h); + spin_unlock(&hugetlb_lock); + + NODEMASK_FREE(node_alloc_noretry); + + return 0; +} + +#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_t nodes_allowed, *n_mask; + + if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) + return -EINVAL; + + if (nid == NUMA_NO_NODE) { + /* + * global hstate attribute + */ + if (!(obey_mempolicy && + init_nodemask_of_mempolicy(&nodes_allowed))) + n_mask = &node_states[N_MEMORY]; + else + n_mask = &nodes_allowed; + } else { + /* + * Node specific request. count adjustment happens in + * set_max_huge_pages() after acquiring hugetlb_lock. + */ + init_nodemask_of_node(&nodes_allowed, nid); + n_mask = &nodes_allowed; + } + + err = set_max_huge_pages(h, count, nid, n_mask); + + return err ? err : len; +} + +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 const 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, + const 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]); + hstate_kobjs[hi] = NULL; + } + + 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]; +}; +static 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 const 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; +} + + +/* + * 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_register_all_nodes(void) { } + +#endif + +static int __init hugetlb_init(void) +{ + int i; + + if (!hugepages_supported()) { + if (hugetlb_max_hstate || default_hstate_max_huge_pages) + pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n"); + return 0; + } + + /* + * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some + * architectures depend on setup being done here. + */ + hugetlb_add_hstate(HUGETLB_PAGE_ORDER); + if (!parsed_default_hugepagesz) { + /* + * If we did not parse a default huge page size, set + * default_hstate_idx to HPAGE_SIZE hstate. And, if the + * number of huge pages for this default size was implicitly + * specified, set that here as well. + * Note that the implicit setting will overwrite an explicit + * setting. A warning will be printed in this case. + */ + default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE)); + if (default_hstate_max_huge_pages) { + if (default_hstate.max_huge_pages) { + char buf[32]; + + string_get_size(huge_page_size(&default_hstate), + 1, STRING_UNITS_2, buf, 32); + pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n", + default_hstate.max_huge_pages, buf); + pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n", + default_hstate_max_huge_pages); + } + default_hstate.max_huge_pages = + default_hstate_max_huge_pages; + } + } + + hugetlb_cma_check(); + 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 + hugetlb_fault_mutex_table = + kmalloc_array(num_fault_mutexes, sizeof(struct mutex), + GFP_KERNEL); + BUG_ON(!hugetlb_fault_mutex_table); + + for (i = 0; i < num_fault_mutexes; i++) + mutex_init(&hugetlb_fault_mutex_table[i]); + return 0; +} +subsys_initcall(hugetlb_init); + +/* Overwritten by architectures with more huge page sizes */ +bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size) +{ + return size == HPAGE_SIZE; +} + +void __init hugetlb_add_hstate(unsigned int order) +{ + struct hstate *h; + unsigned long i; + + if (size_to_hstate(PAGE_SIZE << order)) { + 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_memory_node; + h->next_nid_to_free = first_memory_node; + snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", + huge_page_size(h)/1024); + + parsed_hstate = h; +} + +/* + * hugepages command line processing + * hugepages normally follows a valid hugepagsz or default_hugepagsz + * specification. If not, ignore the hugepages value. hugepages can also + * be the first huge page command line option in which case it implicitly + * specifies the number of huge pages for the default size. + */ +static int __init hugepages_setup(char *s) +{ + unsigned long *mhp; + static unsigned long *last_mhp; + + if (!parsed_valid_hugepagesz) { + pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s); + parsed_valid_hugepagesz = true; + return 0; + } + + /* + * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter + * yet, so this hugepages= parameter goes to the "default hstate". + * Otherwise, it goes with the previously parsed hugepagesz or + * default_hugepagesz. + */ + else if (!hugetlb_max_hstate) + mhp = &default_hstate_max_huge_pages; + else + mhp = &parsed_hstate->max_huge_pages; + + if (mhp == last_mhp) { + pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s); + return 0; + } + + 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=", hugepages_setup); + +/* + * hugepagesz command line processing + * A specific huge page size can only be specified once with hugepagesz. + * hugepagesz is followed by hugepages on the command line. The global + * variable 'parsed_valid_hugepagesz' is used to determine if prior + * hugepagesz argument was valid. + */ +static int __init hugepagesz_setup(char *s) +{ + unsigned long size; + struct hstate *h; + + parsed_valid_hugepagesz = false; + size = (unsigned long)memparse(s, NULL); + + if (!arch_hugetlb_valid_size(size)) { + pr_err("HugeTLB: unsupported hugepagesz=%s\n", s); + return 0; + } + + h = size_to_hstate(size); + if (h) { + /* + * hstate for this size already exists. This is normally + * an error, but is allowed if the existing hstate is the + * default hstate. More specifically, it is only allowed if + * the number of huge pages for the default hstate was not + * previously specified. + */ + if (!parsed_default_hugepagesz || h != &default_hstate || + default_hstate.max_huge_pages) { + pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s); + return 0; + } + + /* + * No need to call hugetlb_add_hstate() as hstate already + * exists. But, do set parsed_hstate so that a following + * hugepages= parameter will be applied to this hstate. + */ + parsed_hstate = h; + parsed_valid_hugepagesz = true; + return 1; + } + + hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT); + parsed_valid_hugepagesz = true; + return 1; +} +__setup("hugepagesz=", hugepagesz_setup); + +/* + * default_hugepagesz command line input + * Only one instance of default_hugepagesz allowed on command line. + */ +static int __init default_hugepagesz_setup(char *s) +{ + unsigned long size; + + parsed_valid_hugepagesz = false; + if (parsed_default_hugepagesz) { + pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s); + return 0; + } + + size = (unsigned long)memparse(s, NULL); + + if (!arch_hugetlb_valid_size(size)) { + pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s); + return 0; + } + + hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT); + parsed_valid_hugepagesz = true; + parsed_default_hugepagesz = true; + default_hstate_idx = hstate_index(size_to_hstate(size)); + + /* + * The number of default huge pages (for this size) could have been + * specified as the first hugetlb parameter: hugepages=X. If so, + * then default_hstate_max_huge_pages is set. If the default huge + * page size is gigantic (>= MAX_ORDER), then the pages must be + * allocated here from bootmem allocator. + */ + if (default_hstate_max_huge_pages) { + default_hstate.max_huge_pages = default_hstate_max_huge_pages; + if (hstate_is_gigantic(&default_hstate)) + hugetlb_hstate_alloc_pages(&default_hstate); + default_hstate_max_huge_pages = 0; + } + + return 1; +} +__setup("default_hugepagesz=", default_hugepagesz_setup); + +static unsigned int allowed_mems_nr(struct hstate *h) +{ + int node; + unsigned int nr = 0; + nodemask_t *mpol_allowed; + unsigned int *array = h->free_huge_pages_node; + gfp_t gfp_mask = htlb_alloc_mask(h); + + mpol_allowed = policy_nodemask_current(gfp_mask); + + for_each_node_mask(node, cpuset_current_mems_allowed) { + if (!mpol_allowed || + (mpol_allowed && node_isset(node, *mpol_allowed))) + nr += array[node]; + } + + return nr; +} + +#ifdef CONFIG_SYSCTL +static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write, + void *buffer, size_t *length, + loff_t *ppos, unsigned long *out) +{ + struct ctl_table dup_table; + + /* + * In order to avoid races with __do_proc_doulongvec_minmax(), we + * can duplicate the @table and alter the duplicate of it. + */ + dup_table = *table; + dup_table.data = out; + + return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos); +} + +static int hugetlb_sysctl_handler_common(bool obey_mempolicy, + struct ctl_table *table, int write, + void *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 -EOPNOTSUPP; + + ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos, + &tmp); + 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 *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 *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 *buffer, size_t *length, loff_t *ppos) +{ + struct hstate *h = &default_hstate; + unsigned long tmp; + int ret; + + if (!hugepages_supported()) + return -EOPNOTSUPP; + + tmp = h->nr_overcommit_huge_pages; + + if (write && hstate_is_gigantic(h)) + return -EINVAL; + + ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos, + &tmp); + 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; + unsigned long total = 0; + + if (!hugepages_supported()) + return; + + for_each_hstate(h) { + unsigned long count = h->nr_huge_pages; + + total += (PAGE_SIZE << huge_page_order(h)) * count; + + if (h == &default_hstate) + seq_printf(m, + "HugePages_Total: %5lu\n" + "HugePages_Free: %5lu\n" + "HugePages_Rsvd: %5lu\n" + "HugePages_Surp: %5lu\n" + "Hugepagesize: %8lu kB\n", + count, + h->free_huge_pages, + h->resv_huge_pages, + h->surplus_huge_pages, + (PAGE_SIZE << huge_page_order(h)) / 1024); + } + + seq_printf(m, "Hugetlb: %8lu kB\n", total / 1024); +} + +int hugetlb_report_node_meminfo(char *buf, int len, int nid) +{ + struct hstate *h = &default_hstate; + + if (!hugepages_supported()) + return 0; + + return sysfs_emit_at(buf, len, + "Node %d HugePages_Total: %5u\n" + "Node %d HugePages_Free: %5u\n" + "Node %d HugePages_Surp: %5u\n", + nid, h->nr_huge_pages_node[nid], + nid, h->free_huge_pages_node[nid], + nid, h->surplus_huge_pages_node[nid]); +} + +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)); +} + +void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm) +{ + seq_printf(m, "HugetlbPages:\t%8lu kB\n", + atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10)); +} + +/* 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. + * + * Apart from cpuset, we also have memory policy mechanism that + * also determines from which node the kernel will allocate memory + * in a NUMA system. So similar to cpuset, we also should consider + * the memory policy of the current task. Similar to the description + * above. + */ + if (delta > 0) { + if (gather_surplus_pages(h, delta) < 0) + goto out; + + if (delta > allowed_mems_nr(h)) { + 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)) { + resv_map_dup_hugetlb_cgroup_uncharge_info(resv); + 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); + hugetlb_cgroup_uncharge_counter(resv, start, end); + 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); + } + + kref_put(&resv->refs, resv_map_release); +} + +static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr) +{ + if (addr & ~(huge_page_mask(hstate_vma(vma)))) + return -EINVAL; + return 0; +} + +static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma) +{ + struct hstate *hstate = hstate_vma(vma); + + return 1UL << huge_page_shift(hstate); +} + +/* + * 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 vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf) +{ + BUG(); + return 0; +} + +/* + * When a new function is introduced to vm_operations_struct and added + * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops. + * This is because under System V memory model, mappings created via + * shmget/shmat with "huge page" specified are backed by hugetlbfs files, + * their original vm_ops are overwritten with shm_vm_ops. + */ +const struct vm_operations_struct hugetlb_vm_ops = { + .fault = hugetlb_vm_op_fault, + .open = hugetlb_vm_op_open, + .close = hugetlb_vm_op_close, + .split = hugetlb_vm_op_split, + .pagesize = hugetlb_vm_op_pagesize, +}; + +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); +} + +bool is_hugetlb_entry_migration(pte_t pte) +{ + swp_entry_t swp; + + if (huge_pte_none(pte) || pte_present(pte)) + return false; + swp = pte_to_swp_entry(pte); + if (is_migration_entry(swp)) + return true; + else + return false; +} + +static bool is_hugetlb_entry_hwpoisoned(pte_t pte) +{ + swp_entry_t swp; + + if (huge_pte_none(pte) || pte_present(pte)) + return false; + swp = pte_to_swp_entry(pte); + if (is_hwpoison_entry(swp)) + return true; + else + return false; +} + +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, dst_entry; + struct page *ptepage; + unsigned long addr; + int cow; + struct hstate *h = hstate_vma(vma); + unsigned long sz = huge_page_size(h); + struct address_space *mapping = vma->vm_file->f_mapping; + struct mmu_notifier_range range; + int ret = 0; + + cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; + + if (cow) { + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src, + vma->vm_start, + vma->vm_end); + mmu_notifier_invalidate_range_start(&range); + } else { + /* + * For shared mappings i_mmap_rwsem must be held to call + * huge_pte_alloc, otherwise the returned ptep could go + * away if part of a shared pmd and another thread calls + * huge_pmd_unshare. + */ + i_mmap_lock_read(mapping); + } + + for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { + spinlock_t *src_ptl, *dst_ptl; + src_pte = huge_pte_offset(src, addr, sz); + 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. + * dst_pte == src_pte is the common case of src/dest sharing. + * + * However, src could have 'unshared' and dst shares with + * another vma. If dst_pte !none, this implies sharing. + * Check here before taking page table lock, and once again + * after taking the lock below. + */ + dst_entry = huge_ptep_get(dst_pte); + if ((dst_pte == src_pte) || !huge_pte_none(dst_entry)) + 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); + dst_entry = huge_ptep_get(dst_pte); + if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) { + /* + * Skip if src entry none. Also, skip in the + * unlikely case dst entry !none as this implies + * sharing with another vma. + */ + ; + } 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_swap_pte_at(src, addr, src_pte, + entry, sz); + } + set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz); + } else { + if (cow) { + /* + * No need to notify as we are downgrading page + * table protection not changing it to point + * to a new page. + * + * See Documentation/vm/mmu_notifier.rst + */ + huge_ptep_set_wrprotect(src, addr, src_pte); + } + entry = huge_ptep_get(src_pte); + ptepage = pte_page(entry); + get_page(ptepage); + page_dup_rmap(ptepage, true); + set_huge_pte_at(dst, addr, dst_pte, entry); + hugetlb_count_add(pages_per_huge_page(h), dst); + } + spin_unlock(src_ptl); + spin_unlock(dst_ptl); + } + + if (cow) + mmu_notifier_invalidate_range_end(&range); + else + i_mmap_unlock_read(mapping); + + 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) +{ + 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); + struct mmu_notifier_range range; + bool force_flush = false; + + WARN_ON(!is_vm_hugetlb_page(vma)); + BUG_ON(start & ~huge_page_mask(h)); + BUG_ON(end & ~huge_page_mask(h)); + + /* + * This is a hugetlb vma, all the pte entries should point + * to huge page. + */ + tlb_change_page_size(tlb, sz); + tlb_start_vma(tlb, vma); + + /* + * If sharing possible, alert mmu notifiers of worst case. + */ + mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start, + end); + adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); + mmu_notifier_invalidate_range_start(&range); + address = start; + for (; address < end; address += sz) { + ptep = huge_pte_offset(mm, address, sz); + if (!ptep) + continue; + + ptl = huge_pte_lock(h, mm, ptep); + if (huge_pmd_unshare(mm, vma, &address, ptep)) { + spin_unlock(ptl); + tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE); + force_flush = true; + continue; + } + + pte = huge_ptep_get(ptep); + if (huge_pte_none(pte)) { + spin_unlock(ptl); + continue; + } + + /* + * 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, sz); + spin_unlock(ptl); + continue; + } + + 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) { + spin_unlock(ptl); + continue; + } + /* + * Mark the VMA as having unmapped its page so that + * future faults in this VMA will fail rather than + * looking like data was lost + */ + set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); + } + + pte = huge_ptep_get_and_clear(mm, address, ptep); + tlb_remove_huge_tlb_entry(h, tlb, ptep, address); + if (huge_pte_dirty(pte)) + set_page_dirty(page); + + hugetlb_count_sub(pages_per_huge_page(h), mm); + page_remove_rmap(page, true); + + spin_unlock(ptl); + tlb_remove_page_size(tlb, page, huge_page_size(h)); + /* + * Bail out after unmapping reference page if supplied + */ + if (ref_page) + break; + } + mmu_notifier_invalidate_range_end(&range); + tlb_end_vma(tlb, vma); + + /* + * If we unshared PMDs, the TLB flush was not recorded in mmu_gather. We + * could defer the flush until now, since by holding i_mmap_rwsem we + * guaranteed that the last refernece would not be dropped. But we must + * do the flushing before we return, as otherwise i_mmap_rwsem will be + * dropped and the last reference to the shared PMDs page might be + * dropped as well. + * + * In theory we could defer the freeing of the PMD pages as well, but + * huge_pmd_unshare() relies on the exact page_count for the PMD page to + * detect sharing, so we cannot defer the release of the page either. + * Instead, do flush now. + */ + if (force_flush) + tlb_flush_mmu_tlbonly(tlb); +} + +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; + unsigned long tlb_start = start; + unsigned long tlb_end = end; + + /* + * If shared PMDs were possibly used within this vma range, adjust + * start/end for worst case tlb flushing. + * Note that we can not be sure if PMDs are shared until we try to + * unmap pages. However, we want to make sure TLB flushing covers + * the largest possible range. + */ + adjust_range_if_pmd_sharing_possible(vma, &tlb_start, &tlb_end); + + mm = vma->vm_mm; + + tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end); + __unmap_hugepage_range(&tlb, vma, start, end, ref_page); + tlb_finish_mmu(&tlb, tlb_start, tlb_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 = vma->vm_file->f_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; + + /* + * Shared VMAs have their own reserves and do not affect + * MAP_PRIVATE accounting but it is possible that a shared + * VMA is using the same page so check and skip such VMAs. + */ + if (iter_vma->vm_flags & VM_MAYSHARE) + continue; + + /* + * 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 vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long address, pte_t *ptep, + struct page *pagecache_page, spinlock_t *ptl) +{ + pte_t pte; + struct hstate *h = hstate_vma(vma); + struct page *old_page, *new_page; + int outside_reserve = 0; + vm_fault_t ret = 0; + unsigned long haddr = address & huge_page_mask(h); + struct mmu_notifier_range range; + + pte = huge_ptep_get(ptep); + 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); + set_huge_ptep_writable(vma, haddr, 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; + + get_page(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, haddr, 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) { + struct address_space *mapping = vma->vm_file->f_mapping; + pgoff_t idx; + u32 hash; + + put_page(old_page); + BUG_ON(huge_pte_none(pte)); + /* + * Drop hugetlb_fault_mutex and i_mmap_rwsem before + * unmapping. unmapping needs to hold i_mmap_rwsem + * in write mode. Dropping i_mmap_rwsem in read mode + * here is OK as COW mappings do not interact with + * PMD sharing. + * + * Reacquire both after unmap operation. + */ + idx = vma_hugecache_offset(h, vma, haddr); + hash = hugetlb_fault_mutex_hash(mapping, idx); + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + i_mmap_unlock_read(mapping); + + unmap_ref_private(mm, vma, old_page, haddr); + + i_mmap_lock_read(mapping); + mutex_lock(&hugetlb_fault_mutex_table[hash]); + spin_lock(ptl); + ptep = huge_pte_offset(mm, haddr, huge_page_size(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 = vmf_error(PTR_ERR(new_page)); + 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); + + mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr, + haddr + huge_page_size(h)); + mmu_notifier_invalidate_range_start(&range); + + /* + * Retake the page table lock to check for racing updates + * before the page tables are altered + */ + spin_lock(ptl); + ptep = huge_pte_offset(mm, haddr, huge_page_size(h)); + if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) { + ClearPagePrivate(new_page); + + /* Break COW */ + huge_ptep_clear_flush(vma, haddr, ptep); + mmu_notifier_invalidate_range(mm, range.start, range.end); + set_huge_pte_at(mm, haddr, ptep, + make_huge_pte(vma, new_page, 1)); + page_remove_rmap(old_page, true); + hugepage_add_new_anon_rmap(new_page, vma, haddr); + set_page_huge_active(new_page); + /* Make the old page be freed below */ + new_page = old_page; + } + spin_unlock(ptl); + mmu_notifier_invalidate_range_end(&range); +out_release_all: + restore_reserve_on_error(h, vma, haddr, new_page); + put_page(new_page); +out_release_old: + put_page(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; +} + +int huge_add_to_page_cache(struct page *page, struct address_space *mapping, + pgoff_t idx) +{ + struct inode *inode = mapping->host; + struct hstate *h = hstate_inode(inode); + int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); + + if (err) + return err; + ClearPagePrivate(page); + + /* + * set page dirty so that it will not be removed from cache/file + * by non-hugetlbfs specific code paths. + */ + set_page_dirty(page); + + spin_lock(&inode->i_lock); + inode->i_blocks += blocks_per_huge_page(h); + spin_unlock(&inode->i_lock); + return 0; +} + +static vm_fault_t hugetlb_no_page(struct mm_struct *mm, + struct vm_area_struct *vma, + struct address_space *mapping, pgoff_t idx, + unsigned long address, pte_t *ptep, unsigned int flags) +{ + struct hstate *h = hstate_vma(vma); + vm_fault_t ret = VM_FAULT_SIGBUS; + int anon_rmap = 0; + unsigned long size; + struct page *page; + pte_t new_pte; + spinlock_t *ptl; + unsigned long haddr = address & huge_page_mask(h); + bool new_page = false; + u32 hash = hugetlb_fault_mutex_hash(mapping, idx); + + /* + * 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_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n", + current->pid); + goto out; + } + + /* + * We can not race with truncation due to holding i_mmap_rwsem. + * i_size is modified when holding i_mmap_rwsem, so check here + * once for faults beyond end of file. + */ + size = i_size_read(mapping->host) >> huge_page_shift(h); + if (idx >= size) + goto out; + +retry: + page = find_lock_page(mapping, idx); + if (!page) { + /* + * Check for page in userfault range + */ + if (userfaultfd_missing(vma)) { + struct vm_fault vmf = { + .vma = vma, + .address = haddr, + .flags = flags, + /* + * Hard to debug if it ends up being + * used by a callee that assumes + * something about the other + * uninitialized fields... same as in + * memory.c + */ + }; + + /* + * vma_lock and hugetlb_fault_mutex must be dropped + * before handling userfault. Also mmap_lock will + * be dropped during handling userfault, any vma + * operation should be careful from here. + */ + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + i_mmap_unlock_read(mapping); + return handle_userfault(&vmf, VM_UFFD_MISSING); + } + + page = alloc_huge_page(vma, haddr, 0); + if (IS_ERR(page)) { + /* + * Returning error will result in faulting task being + * sent SIGBUS. The hugetlb fault mutex prevents two + * tasks from racing to fault in the same page which + * could result in false unable to allocate errors. + * Page migration does not take the fault mutex, but + * does a clear then write of pte's under page table + * lock. Page fault code could race with migration, + * notice the clear pte and try to allocate a page + * here. Before returning error, get ptl and make + * sure there really is no pte entry. + */ + ptl = huge_pte_lock(h, mm, ptep); + if (!huge_pte_none(huge_ptep_get(ptep))) { + ret = 0; + spin_unlock(ptl); + goto out; + } + spin_unlock(ptl); + ret = vmf_error(PTR_ERR(page)); + goto out; + } + clear_huge_page(page, address, pages_per_huge_page(h)); + __SetPageUptodate(page); + new_page = true; + + if (vma->vm_flags & VM_MAYSHARE) { + int err = huge_add_to_page_cache(page, mapping, idx); + if (err) { + put_page(page); + if (err == -EEXIST) + goto retry; + goto out; + } + } 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_LARGE | + 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, haddr) < 0) { + ret = VM_FAULT_OOM; + goto backout_unlocked; + } + /* Just decrements count, does not deallocate */ + vma_end_reservation(h, vma, haddr); + } + + ptl = huge_pte_lock(h, mm, ptep); + ret = 0; + if (!huge_pte_none(huge_ptep_get(ptep))) + goto backout; + + if (anon_rmap) { + ClearPagePrivate(page); + hugepage_add_new_anon_rmap(page, vma, haddr); + } else + page_dup_rmap(page, true); + new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) + && (vma->vm_flags & VM_SHARED))); + set_huge_pte_at(mm, haddr, ptep, new_pte); + + hugetlb_count_add(pages_per_huge_page(h), mm); + 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, page, ptl); + } + + spin_unlock(ptl); + + /* + * Only make newly allocated pages active. Existing pages found + * in the pagecache could be !page_huge_active() if they have been + * isolated for migration. + */ + if (new_page) + set_page_huge_active(page); + + unlock_page(page); +out: + mutex_unlock(&hugetlb_fault_mutex_table[hash]); + i_mmap_unlock_read(mapping); + return ret; + +backout: + spin_unlock(ptl); +backout_unlocked: + unlock_page(page); + restore_reserve_on_error(h, vma, haddr, page); + put_page(page); + goto out; +} + +#ifdef CONFIG_SMP +u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx) +{ + unsigned long key[2]; + u32 hash; + + key[0] = (unsigned long) mapping; + key[1] = idx; + + 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. + */ +u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx) +{ + return 0; +} +#endif + +vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long address, unsigned int flags) +{ + pte_t *ptep, entry; + spinlock_t *ptl; + vm_fault_t 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; + unsigned long haddr = address & huge_page_mask(h); + + ptep = huge_pte_offset(mm, haddr, huge_page_size(h)); + if (ptep) { + /* + * Since we hold no locks, ptep could be stale. That is + * OK as we are only making decisions based on content and + * not actually modifying content here. + */ + 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)); + } + + /* + * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold + * until finished with ptep. This serves two purposes: + * 1) It prevents huge_pmd_unshare from being called elsewhere + * and making the ptep no longer valid. + * 2) It synchronizes us with i_size modifications during truncation. + * + * ptep could have already be assigned via huge_pte_offset. That + * is OK, as huge_pte_alloc will return the same value unless + * something has changed. + */ + mapping = vma->vm_file->f_mapping; + i_mmap_lock_read(mapping); + ptep = huge_pte_alloc(mm, haddr, huge_page_size(h)); + if (!ptep) { + i_mmap_unlock_read(mapping); + return VM_FAULT_OOM; + } + + /* + * 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. + */ + idx = vma_hugecache_offset(h, vma, haddr); + hash = hugetlb_fault_mutex_hash(mapping, idx); + mutex_lock(&hugetlb_fault_mutex_table[hash]); + + entry = huge_ptep_get(ptep); + if (huge_pte_none(entry)) + /* + * hugetlb_no_page will drop vma lock and hugetlb fault + * mutex internally, which make us return immediately. + */ + return hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags); + + 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 + * an 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, haddr) < 0) { + ret = VM_FAULT_OOM; + goto out_mutex; + } + /* Just decrements count, does not deallocate */ + vma_end_reservation(h, vma, haddr); + + if (!(vma->vm_flags & VM_MAYSHARE)) + pagecache_page = hugetlbfs_pagecache_page(h, + vma, haddr); + } + + 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, + pagecache_page, ptl); + goto out_put_page; + } + entry = huge_pte_mkdirty(entry); + } + entry = pte_mkyoung(entry); + if (huge_ptep_set_access_flags(vma, haddr, ptep, entry, + flags & FAULT_FLAG_WRITE)) + update_mmu_cache(vma, haddr, 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(&hugetlb_fault_mutex_table[hash]); + i_mmap_unlock_read(mapping); + /* + * 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; +} + +/* + * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with + * modifications for huge pages. + */ +int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, + pte_t *dst_pte, + struct vm_area_struct *dst_vma, + unsigned long dst_addr, + unsigned long src_addr, + struct page **pagep) +{ + struct address_space *mapping; + pgoff_t idx; + unsigned long size; + int vm_shared = dst_vma->vm_flags & VM_SHARED; + struct hstate *h = hstate_vma(dst_vma); + pte_t _dst_pte; + spinlock_t *ptl; + int ret; + struct page *page; + + if (!*pagep) { + /* If a page already exists, then it's UFFDIO_COPY for + * a non-missing case. Return -EEXIST. + */ + if (vm_shared && + hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) { + ret = -EEXIST; + goto out; + } + + page = alloc_huge_page(dst_vma, dst_addr, 0); + if (IS_ERR(page)) { + ret = -ENOMEM; + goto out; + } + + ret = copy_huge_page_from_user(page, + (const void __user *) src_addr, + pages_per_huge_page(h), false); + + /* fallback to copy_from_user outside mmap_lock */ + if (unlikely(ret)) { + ret = -ENOENT; + *pagep = page; + /* don't free the page */ + goto out; + } + } else { + page = *pagep; + *pagep = NULL; + } + + /* + * The memory barrier inside __SetPageUptodate makes sure that + * preceding stores to the page contents become visible before + * the set_pte_at() write. + */ + __SetPageUptodate(page); + + mapping = dst_vma->vm_file->f_mapping; + idx = vma_hugecache_offset(h, dst_vma, dst_addr); + + /* + * If shared, add to page cache + */ + if (vm_shared) { + size = i_size_read(mapping->host) >> huge_page_shift(h); + ret = -EFAULT; + if (idx >= size) + goto out_release_nounlock; + + /* + * Serialization between remove_inode_hugepages() and + * huge_add_to_page_cache() below happens through the + * hugetlb_fault_mutex_table that here must be hold by + * the caller. + */ + ret = huge_add_to_page_cache(page, mapping, idx); + if (ret) + goto out_release_nounlock; + } + + ptl = huge_pte_lockptr(h, dst_mm, dst_pte); + spin_lock(ptl); + + /* + * Recheck the i_size after holding PT lock to make sure not + * to leave any page mapped (as page_mapped()) beyond the end + * of the i_size (remove_inode_hugepages() is strict about + * enforcing that). If we bail out here, we'll also leave a + * page in the radix tree in the vm_shared case beyond the end + * of the i_size, but remove_inode_hugepages() will take care + * of it as soon as we drop the hugetlb_fault_mutex_table. + */ + size = i_size_read(mapping->host) >> huge_page_shift(h); + ret = -EFAULT; + if (idx >= size) + goto out_release_unlock; + + ret = -EEXIST; + if (!huge_pte_none(huge_ptep_get(dst_pte))) + goto out_release_unlock; + + if (vm_shared) { + page_dup_rmap(page, true); + } else { + ClearPagePrivate(page); + hugepage_add_new_anon_rmap(page, dst_vma, dst_addr); + } + + _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE); + if (dst_vma->vm_flags & VM_WRITE) + _dst_pte = huge_pte_mkdirty(_dst_pte); + _dst_pte = pte_mkyoung(_dst_pte); + + set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); + + (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte, + dst_vma->vm_flags & VM_WRITE); + hugetlb_count_add(pages_per_huge_page(h), dst_mm); + + /* No need to invalidate - it was non-present before */ + update_mmu_cache(dst_vma, dst_addr, dst_pte); + + spin_unlock(ptl); + set_page_huge_active(page); + if (vm_shared) + unlock_page(page); + ret = 0; +out: + return ret; +out_release_unlock: + spin_unlock(ptl); + if (vm_shared) + unlock_page(page); +out_release_nounlock: + put_page(page); + goto out; +} + +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, int *locked) +{ + unsigned long pfn_offset; + unsigned long vaddr = *position; + unsigned long remainder = *nr_pages; + struct hstate *h = hstate_vma(vma); + int err = -EFAULT; + + 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 (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), + huge_page_size(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)))) { + vm_fault_t ret; + unsigned int fault_flags = 0; + + if (pte) + spin_unlock(ptl); + if (flags & FOLL_WRITE) + fault_flags |= FAULT_FLAG_WRITE; + if (locked) + fault_flags |= FAULT_FLAG_ALLOW_RETRY | + FAULT_FLAG_KILLABLE; + if (flags & FOLL_NOWAIT) + fault_flags |= FAULT_FLAG_ALLOW_RETRY | + FAULT_FLAG_RETRY_NOWAIT; + if (flags & FOLL_TRIED) { + /* + * Note: FAULT_FLAG_ALLOW_RETRY and + * FAULT_FLAG_TRIED can co-exist + */ + fault_flags |= FAULT_FLAG_TRIED; + } + ret = hugetlb_fault(mm, vma, vaddr, fault_flags); + if (ret & VM_FAULT_ERROR) { + err = vm_fault_to_errno(ret, flags); + remainder = 0; + break; + } + if (ret & VM_FAULT_RETRY) { + if (locked && + !(fault_flags & FAULT_FLAG_RETRY_NOWAIT)) + *locked = 0; + *nr_pages = 0; + /* + * VM_FAULT_RETRY must not return an + * error, it will return zero + * instead. + * + * No need to update "position" as the + * caller will not check it after + * *nr_pages is set to 0. + */ + return i; + } + continue; + } + + pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; + page = pte_page(huge_ptep_get(pte)); + + /* + * If subpage information not requested, update counters + * and skip the same_page loop below. + */ + if (!pages && !vmas && !pfn_offset && + (vaddr + huge_page_size(h) < vma->vm_end) && + (remainder >= pages_per_huge_page(h))) { + vaddr += huge_page_size(h); + remainder -= pages_per_huge_page(h); + i += pages_per_huge_page(h); + spin_unlock(ptl); + continue; + } + +same_page: + if (pages) { + pages[i] = mem_map_offset(page, pfn_offset); + /* + * try_grab_page() should always succeed here, because: + * a) we hold the ptl lock, and b) we've just checked + * that the huge page is present in the page tables. If + * the huge page is present, then the tail pages must + * also be present. The ptl prevents the head page and + * tail pages from being rearranged in any way. So this + * page must be available at this point, unless the page + * refcount overflowed: + */ + if (WARN_ON_ONCE(!try_grab_page(pages[i], flags))) { + spin_unlock(ptl); + remainder = 0; + err = -ENOMEM; + break; + } + } + + 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; + /* + * setting position is actually required only if remainder is + * not zero but it's faster not to add a "if (remainder)" + * branch. + */ + *position = vaddr; + + return i ? i : err; +} + +#ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE +/* + * ARCHes with special requirements for evicting HUGETLB backing TLB entries can + * implement this. + */ +#define flush_hugetlb_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) +#endif + +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; + bool shared_pmd = false; + struct mmu_notifier_range range; + + /* + * In the case of shared PMDs, the area to flush could be beyond + * start/end. Set range.start/range.end to cover the maximum possible + * range if PMD sharing is possible. + */ + mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, + 0, vma, mm, start, end); + adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); + + BUG_ON(address >= end); + flush_cache_range(vma, range.start, range.end); + + mmu_notifier_invalidate_range_start(&range); + 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, huge_page_size(h)); + if (!ptep) + continue; + ptl = huge_pte_lock(h, mm, ptep); + if (huge_pmd_unshare(mm, vma, &address, ptep)) { + pages++; + spin_unlock(ptl); + shared_pmd = true; + 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_swap_pte_at(mm, address, ptep, + newpte, huge_page_size(h)); + pages++; + } + spin_unlock(ptl); + continue; + } + if (!huge_pte_none(pte)) { + pte_t old_pte; + + old_pte = huge_ptep_modify_prot_start(vma, address, ptep); + pte = pte_mkhuge(huge_pte_modify(old_pte, newprot)); + pte = arch_make_huge_pte(pte, vma, NULL, 0); + huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, 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. If we actually + * did unshare a page of pmds, flush the range corresponding to the pud. + */ + if (shared_pmd) + flush_hugetlb_tlb_range(vma, range.start, range.end); + else + flush_hugetlb_tlb_range(vma, start, end); + /* + * No need to call mmu_notifier_invalidate_range() we are downgrading + * page table protection not changing it to point to a new page. + * + * See Documentation/vm/mmu_notifier.rst + */ + i_mmap_unlock_write(vma->vm_file->f_mapping); + mmu_notifier_invalidate_range_end(&range); + + 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, add = -1; + struct hstate *h = hstate_inode(inode); + struct hugepage_subpool *spool = subpool_inode(inode); + struct resv_map *resv_map; + struct hugetlb_cgroup *h_cg = NULL; + long gbl_reserve, regions_needed = 0; + + /* This should never happen */ + if (from > to) { + VM_WARN(1, "%s called with a negative range\n", __func__); + return -EINVAL; + } + + /* + * 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 can not be NULL as hugetlb_reserve_pages is only + * called for inodes for which resv_maps were created (see + * hugetlbfs_get_inode). + */ + resv_map = inode_resv_map(inode); + + chg = region_chg(resv_map, from, to, ®ions_needed); + + } else { + /* Private mapping. */ + 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; + } + + ret = hugetlb_cgroup_charge_cgroup_rsvd( + hstate_index(h), chg * pages_per_huge_page(h), &h_cg); + + if (ret < 0) { + ret = -ENOMEM; + goto out_err; + } + + if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) { + /* For private mappings, the hugetlb_cgroup uncharge info hangs + * of the resv_map. + */ + resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h); + } + + /* + * 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_uncharge_cgroup; + } + + /* + * 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) { + goto out_put_pages; + } + + /* + * 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) { + add = region_add(resv_map, from, to, regions_needed, h, h_cg); + + if (unlikely(add < 0)) { + hugetlb_acct_memory(h, -gbl_reserve); + ret = add; + goto out_put_pages; + } else if (unlikely(chg > add)) { + /* + * pages in this range were added to the reserve + * map between region_chg and region_add. This + * indicates a race with alloc_huge_page. Adjust + * the subpool and reserve counts modified above + * based on the difference. + */ + long rsv_adjust; + + /* + * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the + * reference to h_cg->css. See comment below for detail. + */ + hugetlb_cgroup_uncharge_cgroup_rsvd( + hstate_index(h), + (chg - add) * pages_per_huge_page(h), h_cg); + + rsv_adjust = hugepage_subpool_put_pages(spool, + chg - add); + hugetlb_acct_memory(h, -rsv_adjust); + } else if (h_cg) { + /* + * The file_regions will hold their own reference to + * h_cg->css. So we should release the reference held + * via hugetlb_cgroup_charge_cgroup_rsvd() when we are + * done. + */ + hugetlb_cgroup_put_rsvd_cgroup(h_cg); + } + } + return 0; +out_put_pages: + /* put back original number of pages, chg */ + (void)hugepage_subpool_put_pages(spool, chg); +out_uncharge_cgroup: + hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h), + chg * pages_per_huge_page(h), h_cg); +out_err: + if (!vma || vma->vm_flags & VM_MAYSHARE) + /* Only call region_abort if the region_chg succeeded but the + * region_add failed or didn't run. + */ + if (chg >= 0 && add < 0) + region_abort(resv_map, from, to, regions_needed); + if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) + kref_put(&resv_map->refs, resv_map_release); + return ret; +} + +long hugetlb_unreserve_pages(struct inode *inode, long start, long end, + 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; + + /* + * Since this routine can be called in the evict inode path for all + * hugetlbfs inodes, resv_map could be NULL. + */ + if (resv_map) { + chg = region_del(resv_map, start, end); + /* + * region_del() can fail in the rare case where a region + * must be split and another region descriptor can not be + * allocated. If end == LONG_MAX, it will not fail. + */ + if (chg < 0) + return chg; + } + + 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); + + return 0; +} + +#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_CLEAR_MASK; + unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK; + + /* + * 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 bool 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 && range_in_vma(vma, base, end)) + return true; + return false; +} + +/* + * Determine if start,end range within vma could be mapped by shared pmd. + * If yes, adjust start and end to cover range associated with possible + * shared pmd mappings. + */ +void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, + unsigned long *start, unsigned long *end) +{ + unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE), + v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE); + + /* + * vma need span at least one aligned PUD size and the start,end range + * must at least partialy within it. + */ + if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) || + (*end <= v_start) || (*start >= v_end)) + return; + + /* Extend the range to be PUD aligned for a worst case scenario */ + if (*start > v_start) + *start = ALIGN_DOWN(*start, PUD_SIZE); + + if (*end < v_end) + *end = ALIGN(*end, PUD_SIZE); +} + +/* + * 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. + * + * This routine must be called with i_mmap_rwsem held in at least read mode if + * sharing is possible. For hugetlbfs, this prevents removal of any page + * table entries associated with the address space. This is important as we + * are setting up sharing based on existing page table entries (mappings). + * + * NOTE: This routine is only called from huge_pte_alloc. Some callers of + * huge_pte_alloc know that sharing is not possible and do not take + * i_mmap_rwsem as a performance optimization. This is handled by the + * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is + * only required for subsequent processing. + */ +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_assert_locked(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, + vma_mmu_pagesize(svma)); + if (spte) { + get_page(virt_to_page(spte)); + break; + } + } + } + + if (!spte) + goto out; + + ptl = huge_pte_lock(hstate_vma(vma), mm, spte); + if (pud_none(*pud)) { + pud_populate(mm, pud, + (pmd_t *)((unsigned long)spte & PAGE_MASK)); + mm_inc_nr_pmds(mm); + } else { + put_page(virt_to_page(spte)); + } + spin_unlock(ptl); +out: + pte = (pte_t *)pmd_alloc(mm, pud, addr); + return pte; +} + +/* + * unmap huge page backed by shared pte. + * + * Hugetlb pte page is ref counted at the time of mapping. If pte is shared + * indicated by page_count > 1, unmap is achieved by clearing pud and + * decrementing the ref count. If count == 1, the pte page is not shared. + * + * Called with page table lock held and i_mmap_rwsem held in write mode. + * + * 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, struct vm_area_struct *vma, + unsigned long *addr, pte_t *ptep) +{ + pgd_t *pgd = pgd_offset(mm, *addr); + p4d_t *p4d = p4d_offset(pgd, *addr); + pud_t *pud = pud_offset(p4d, *addr); + + i_mmap_assert_write_locked(vma->vm_file->f_mapping); + 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); + /* + * This update of passed address optimizes loops sequentially + * processing addresses in increments of huge page size (PMD_SIZE + * in this case). By clearing the pud, a PUD_SIZE area is unmapped. + * Update address to the 'last page' in the cleared area so that + * calling loop can move to first page past this area. + */ + *addr |= PUD_SIZE - PMD_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; +} + +int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long *addr, pte_t *ptep) +{ + return 0; +} + +void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, + unsigned long *start, unsigned long *end) +{ +} +#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; + p4d_t *p4d; + pud_t *pud; + pte_t *pte = NULL; + + pgd = pgd_offset(mm, addr); + p4d = p4d_alloc(mm, pgd, addr); + if (!p4d) + return NULL; + pud = pud_alloc(mm, p4d, 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_present(*pte) && !pte_huge(*pte)); + + return pte; +} + +/* + * huge_pte_offset() - Walk the page table to resolve the hugepage + * entry at address @addr + * + * Return: Pointer to page table entry (PUD or PMD) for + * address @addr, or NULL if a !p*d_present() entry is encountered and the + * size @sz doesn't match the hugepage size at this level of the page + * table. + */ +pte_t *huge_pte_offset(struct mm_struct *mm, + unsigned long addr, unsigned long sz) +{ + pgd_t *pgd; + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + + pgd = pgd_offset(mm, addr); + if (!pgd_present(*pgd)) + return NULL; + p4d = p4d_offset(pgd, addr); + if (!p4d_present(*p4d)) + return NULL; + + pud = pud_offset(p4d, addr); + if (sz == PUD_SIZE) + /* must be pud huge, non-present or none */ + return (pte_t *)pud; + if (!pud_present(*pud)) + return NULL; + /* must have a valid entry and size to go further */ + + pmd = pmd_offset(pud, addr); + /* must be pmd huge, non-present or none */ + 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_pd(struct vm_area_struct *vma, + unsigned long address, hugepd_t hpd, int flags, int pdshift) +{ + WARN(1, "hugepd follow called with no support for hugepage directory format\n"); + return NULL; +} + +struct page * __weak +follow_huge_pmd_pte(struct vm_area_struct *vma, unsigned long address, int flags) +{ + struct hstate *h = hstate_vma(vma); + struct mm_struct *mm = vma->vm_mm; + struct page *page = NULL; + spinlock_t *ptl; + pte_t *ptep, pte; + + /* FOLL_GET and FOLL_PIN are mutually exclusive. */ + if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == + (FOLL_PIN | FOLL_GET))) + return NULL; + +retry: + ptep = huge_pte_offset(mm, address, huge_page_size(h)); + if (!ptep) + return NULL; + + ptl = huge_pte_lock(h, mm, ptep); + pte = huge_ptep_get(ptep); + if (pte_present(pte)) { + page = pte_page(pte) + + ((address & ~huge_page_mask(h)) >> PAGE_SHIFT); + /* + * try_grab_page() should always succeed here, because: a) we + * hold the pmd (ptl) lock, and b) we've just checked that the + * huge pmd (head) page is present in the page tables. The ptl + * prevents the head page and tail pages from being rearranged + * in any way. So this page must be available at this point, + * unless the page refcount overflowed: + */ + if (WARN_ON_ONCE(!try_grab_page(page, flags))) { + page = NULL; + goto out; + } + } else { + if (is_hugetlb_entry_migration(pte)) { + spin_unlock(ptl); + __migration_entry_wait(mm, ptep, 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 | FOLL_PIN)) + return NULL; + + return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT); +} + +struct page * __weak +follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags) +{ + if (flags & (FOLL_GET | FOLL_PIN)) + return NULL; + + return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT); +} + +int isolate_hugetlb(struct page *page, struct list_head *list) +{ + int ret = 0; + + spin_lock(&hugetlb_lock); + if (!PageHeadHuge(page) || !page_huge_active(page) || + !get_page_unless_zero(page)) { + ret = -EBUSY; + 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); +} + +void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason) +{ + struct hstate *h = page_hstate(oldpage); + + hugetlb_cgroup_migrate(oldpage, newpage); + set_page_owner_migrate_reason(newpage, reason); + + /* + * transfer temporary state of the new huge page. This is + * reverse to other transitions because the newpage is going to + * be final while the old one will be freed so it takes over + * the temporary status. + * + * Also note that we have to transfer the per-node surplus state + * here as well otherwise the global surplus count will not match + * the per-node's. + */ + if (PageHugeTemporary(newpage)) { + int old_nid = page_to_nid(oldpage); + int new_nid = page_to_nid(newpage); + + SetPageHugeTemporary(oldpage); + ClearPageHugeTemporary(newpage); + + spin_lock(&hugetlb_lock); + if (h->surplus_huge_pages_node[old_nid]) { + h->surplus_huge_pages_node[old_nid]--; + h->surplus_huge_pages_node[new_nid]++; + } + spin_unlock(&hugetlb_lock); + } +} + +#ifdef CONFIG_CMA +static bool cma_reserve_called __initdata; + +static int __init cmdline_parse_hugetlb_cma(char *p) +{ + hugetlb_cma_size = memparse(p, &p); + return 0; +} + +early_param("hugetlb_cma", cmdline_parse_hugetlb_cma); + +void __init hugetlb_cma_reserve(int order) +{ + unsigned long size, reserved, per_node; + int nid; + + cma_reserve_called = true; + + if (!hugetlb_cma_size) + return; + + if (hugetlb_cma_size < (PAGE_SIZE << order)) { + pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n", + (PAGE_SIZE << order) / SZ_1M); + return; + } + + /* + * If 3 GB area is requested on a machine with 4 numa nodes, + * let's allocate 1 GB on first three nodes and ignore the last one. + */ + per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes); + pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n", + hugetlb_cma_size / SZ_1M, per_node / SZ_1M); + + reserved = 0; + for_each_node_state(nid, N_ONLINE) { + int res; + char name[CMA_MAX_NAME]; + + size = min(per_node, hugetlb_cma_size - reserved); + size = round_up(size, PAGE_SIZE << order); + + snprintf(name, sizeof(name), "hugetlb%d", nid); + res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order, + 0, false, name, + &hugetlb_cma[nid], nid); + if (res) { + pr_warn("hugetlb_cma: reservation failed: err %d, node %d", + res, nid); + continue; + } + + reserved += size; + pr_info("hugetlb_cma: reserved %lu MiB on node %d\n", + size / SZ_1M, nid); + + if (reserved >= hugetlb_cma_size) + break; + } +} + +void __init hugetlb_cma_check(void) +{ + if (!hugetlb_cma_size || cma_reserve_called) + return; + + pr_warn("hugetlb_cma: the option isn't supported by current arch\n"); +} + +#endif /* CONFIG_CMA */ |