| // 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 <linux/migrate.h> |
| #include <linux/nospec.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/page_owner.h> |
| #include "internal.h" |
| #include "hugetlb_vmemmap.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]; |
| static unsigned long hugetlb_cma_size_in_node[MAX_NUMNODES] __initdata; |
| static bool hugetlb_cma_page(struct page *page, unsigned int order) |
| { |
| return cma_pages_valid(hugetlb_cma[page_to_nid(page)], page, |
| 1 << order); |
| } |
| #else |
| static bool hugetlb_cma_page(struct page *page, unsigned int order) |
| { |
| return false; |
| } |
| #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; |
| static unsigned int default_hugepages_in_node[MAX_NUMNODES] __initdata; |
| |
| /* |
| * 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; |
| |
| /* Forward declaration */ |
| static int hugetlb_acct_memory(struct hstate *h, long delta); |
| |
| static inline bool subpool_is_free(struct hugepage_subpool *spool) |
| { |
| if (spool->count) |
| return false; |
| if (spool->max_hpages != -1) |
| return spool->used_hpages == 0; |
| if (spool->min_hpages != -1) |
| return spool->rsv_hpages == spool->min_hpages; |
| |
| return true; |
| } |
| |
| static inline void unlock_or_release_subpool(struct hugepage_subpool *spool, |
| unsigned long irq_flags) |
| { |
| spin_unlock_irqrestore(&spool->lock, irq_flags); |
| |
| /* 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 (subpool_is_free(spool)) { |
| 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) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&spool->lock, flags); |
| BUG_ON(!spool->count); |
| spool->count--; |
| unlock_or_release_subpool(spool, flags); |
| } |
| |
| /* |
| * 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_irq(&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_irq(&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; |
| unsigned long flags; |
| |
| if (!spool) |
| return delta; |
| |
| spin_lock_irqsave(&spool->lock, flags); |
| |
| 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, flags); |
| |
| 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->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); |
| } |
| } |
| |
| static inline long |
| hugetlb_resv_map_add(struct resv_map *map, struct file_region *rg, long from, |
| long to, struct hstate *h, struct hugetlb_cgroup *cg, |
| long *regions_needed) |
| { |
| struct file_region *nrg; |
| |
| if (!regions_needed) { |
| nrg = get_file_region_entry_from_cache(map, from, to); |
| record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg); |
| list_add(&nrg->link, rg->link.prev); |
| coalesce_file_region(map, nrg); |
| } else |
| *regions_needed += 1; |
| |
| return to - from; |
| } |
| |
| /* |
| * 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; |
| |
| 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 += hugetlb_resv_map_add(resv, rg, |
| last_accounted_offset, |
| rg->from, h, h_cg, |
| regions_needed); |
| |
| last_accounted_offset = rg->to; |
| } |
| |
| /* Handle the case where our range extends beyond |
| * last_accounted_offset. |
| */ |
| if (last_accounted_offset < t) |
| add += hugetlb_resv_map_add(resv, rg, last_accounted_offset, |
| t, h, h_cg, regions_needed); |
| |
| 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 existing 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); |
| 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; |
| } |
| |
| /* |
| * Reset and decrement one ref on hugepage private reservation. |
| * Called with mm->mmap_sem writer semaphore held. |
| * This function should be only used by move_vma() and operate on |
| * same sized vma. It should never come here with last ref on the |
| * reservation. |
| */ |
| void clear_vma_resv_huge_pages(struct vm_area_struct *vma) |
| { |
| /* |
| * Clear the old hugetlb private page reservation. |
| * It has already been transferred to new_vma. |
| * |
| * During a mremap() operation of a hugetlb vma we call move_vma() |
| * which copies vma into new_vma and unmaps vma. After the copy |
| * operation both new_vma and vma share a reference to the resv_map |
| * struct, and at that point vma is about to be unmapped. We don't |
| * want to return the reservation to the pool at unmap of vma because |
| * the reservation still lives on in new_vma, so simply decrement the |
| * ref here and remove the resv_map reference from this vma. |
| */ |
| struct resv_map *reservations = vma_resv_map(vma); |
| |
| if (reservations && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| resv_map_put_hugetlb_cgroup_uncharge_info(reservations); |
| kref_put(&reservations->refs, resv_map_release); |
| } |
| |
| reset_vma_resv_huge_pages(vma); |
| } |
| |
| /* 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); |
| |
| lockdep_assert_held(&hugetlb_lock); |
| VM_BUG_ON_PAGE(page_count(page), page); |
| |
| list_move(&page->lru, &h->hugepage_freelists[nid]); |
| h->free_huge_pages++; |
| h->free_huge_pages_node[nid]++; |
| SetHPageFreed(page); |
| } |
| |
| static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid) |
| { |
| struct page *page; |
| bool pin = !!(current->flags & PF_MEMALLOC_PIN); |
| |
| lockdep_assert_held(&hugetlb_lock); |
| list_for_each_entry(page, &h->hugepage_freelists[nid], lru) { |
| if (pin && !is_pinnable_page(page)) |
| continue; |
| |
| if (PageHWPoison(page)) |
| continue; |
| |
| list_move(&page->lru, &h->hugepage_activelist); |
| set_page_refcounted(page); |
| ClearHPageFreed(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 = NULL; |
| 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); |
| |
| if (mpol_is_preferred_many(mpol)) { |
| page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); |
| |
| /* Fallback to all nodes if page==NULL */ |
| nodemask = NULL; |
| } |
| |
| if (!page) |
| page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); |
| |
| if (page && !avoid_reserve && vma_has_reserves(vma, chg)) { |
| SetHPageRestoreReserve(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 remove_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--) |
| |
| /* used to demote non-gigantic_huge pages as well */ |
| static void __destroy_compound_gigantic_page(struct page *page, |
| unsigned int order, bool demote) |
| { |
| 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)) { |
| p->mapping = NULL; |
| clear_compound_head(p); |
| if (!demote) |
| set_page_refcounted(p); |
| } |
| |
| set_compound_order(page, 0); |
| #ifdef CONFIG_64BIT |
| page[1].compound_nr = 0; |
| #endif |
| __ClearPageHead(page); |
| } |
| |
| static void destroy_compound_hugetlb_page_for_demote(struct page *page, |
| unsigned int order) |
| { |
| __destroy_compound_gigantic_page(page, order, true); |
| } |
| |
| #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE |
| static void destroy_compound_gigantic_page(struct page *page, |
| unsigned int order) |
| { |
| __destroy_compound_gigantic_page(page, order, false); |
| } |
| |
| 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 = pages_per_huge_page(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 |
| |
| /* |
| * Remove hugetlb page from lists, and update dtor so that page appears |
| * as just a compound page. |
| * |
| * A reference is held on the page, except in the case of demote. |
| * |
| * Must be called with hugetlb lock held. |
| */ |
| static void __remove_hugetlb_page(struct hstate *h, struct page *page, |
| bool adjust_surplus, |
| bool demote) |
| { |
| int nid = page_to_nid(page); |
| |
| VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); |
| VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page); |
| |
| lockdep_assert_held(&hugetlb_lock); |
| if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) |
| return; |
| |
| list_del(&page->lru); |
| |
| if (HPageFreed(page)) { |
| h->free_huge_pages--; |
| h->free_huge_pages_node[nid]--; |
| } |
| if (adjust_surplus) { |
| h->surplus_huge_pages--; |
| h->surplus_huge_pages_node[nid]--; |
| } |
| |
| /* |
| * Very subtle |
| * |
| * For non-gigantic pages set the destructor to the normal compound |
| * page dtor. This is needed in case someone takes an additional |
| * temporary ref to the page, and freeing is delayed until they drop |
| * their reference. |
| * |
| * For gigantic pages set the destructor to the null dtor. This |
| * destructor will never be called. Before freeing the gigantic |
| * page destroy_compound_gigantic_page will turn the compound page |
| * into a simple group of pages. After this the destructor does not |
| * apply. |
| * |
| * This handles the case where more than one ref is held when and |
| * after update_and_free_page is called. |
| * |
| * In the case of demote we do not ref count the page as it will soon |
| * be turned into a page of smaller size. |
| */ |
| if (!demote) |
| set_page_refcounted(page); |
| if (hstate_is_gigantic(h)) |
| set_compound_page_dtor(page, NULL_COMPOUND_DTOR); |
| else |
| set_compound_page_dtor(page, COMPOUND_PAGE_DTOR); |
| |
| h->nr_huge_pages--; |
| h->nr_huge_pages_node[nid]--; |
| } |
| |
| static void remove_hugetlb_page(struct hstate *h, struct page *page, |
| bool adjust_surplus) |
| { |
| __remove_hugetlb_page(h, page, adjust_surplus, false); |
| } |
| |
| static void remove_hugetlb_page_for_demote(struct hstate *h, struct page *page, |
| bool adjust_surplus) |
| { |
| __remove_hugetlb_page(h, page, adjust_surplus, true); |
| } |
| |
| static void add_hugetlb_page(struct hstate *h, struct page *page, |
| bool adjust_surplus) |
| { |
| int zeroed; |
| int nid = page_to_nid(page); |
| |
| VM_BUG_ON_PAGE(!HPageVmemmapOptimized(page), page); |
| |
| lockdep_assert_held(&hugetlb_lock); |
| |
| INIT_LIST_HEAD(&page->lru); |
| h->nr_huge_pages++; |
| h->nr_huge_pages_node[nid]++; |
| |
| if (adjust_surplus) { |
| h->surplus_huge_pages++; |
| h->surplus_huge_pages_node[nid]++; |
| } |
| |
| set_compound_page_dtor(page, HUGETLB_PAGE_DTOR); |
| set_page_private(page, 0); |
| SetHPageVmemmapOptimized(page); |
| |
| /* |
| * This page is about to be managed by the hugetlb allocator and |
| * should have no users. Drop our reference, and check for others |
| * just in case. |
| */ |
| zeroed = put_page_testzero(page); |
| if (!zeroed) |
| /* |
| * It is VERY unlikely soneone else has taken a ref on |
| * the page. In this case, we simply return as the |
| * hugetlb destructor (free_huge_page) will be called |
| * when this other ref is dropped. |
| */ |
| return; |
| |
| arch_clear_hugepage_flags(page); |
| enqueue_huge_page(h, page); |
| } |
| |
| 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; |
| |
| if (alloc_huge_page_vmemmap(h, page)) { |
| spin_lock_irq(&hugetlb_lock); |
| /* |
| * If we cannot allocate vmemmap pages, just refuse to free the |
| * page and put the page back on the hugetlb free list and treat |
| * as a surplus page. |
| */ |
| add_hugetlb_page(h, page, true); |
| spin_unlock_irq(&hugetlb_lock); |
| return; |
| } |
| |
| 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); |
| } |
| |
| /* |
| * Non-gigantic pages demoted from CMA allocated gigantic pages |
| * need to be given back to CMA in free_gigantic_page. |
| */ |
| if (hstate_is_gigantic(h) || |
| hugetlb_cma_page(page, huge_page_order(h))) { |
| destroy_compound_gigantic_page(page, huge_page_order(h)); |
| free_gigantic_page(page, huge_page_order(h)); |
| } else { |
| __free_pages(page, huge_page_order(h)); |
| } |
| } |
| |
| /* |
| * As update_and_free_page() can be called under any context, so we cannot |
| * use GFP_KERNEL to allocate vmemmap pages. However, we can defer the |
| * actual freeing in a workqueue to prevent from using GFP_ATOMIC to allocate |
| * the vmemmap pages. |
| * |
| * 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_hpage_workfn() 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; |
| |
| node = llist_del_all(&hpage_freelist); |
| |
| while (node) { |
| struct page *page; |
| struct hstate *h; |
| |
| page = container_of((struct address_space **)node, |
| struct page, mapping); |
| node = node->next; |
| page->mapping = NULL; |
| /* |
| * The VM_BUG_ON_PAGE(!PageHuge(page), page) in page_hstate() |
| * is going to trigger because a previous call to |
| * remove_hugetlb_page() will set_compound_page_dtor(page, |
| * NULL_COMPOUND_DTOR), so do not use page_hstate() directly. |
| */ |
| h = size_to_hstate(page_size(page)); |
| |
| __update_and_free_page(h, page); |
| |
| cond_resched(); |
| } |
| } |
| static DECLARE_WORK(free_hpage_work, free_hpage_workfn); |
| |
| static inline void flush_free_hpage_work(struct hstate *h) |
| { |
| if (free_vmemmap_pages_per_hpage(h)) |
| flush_work(&free_hpage_work); |
| } |
| |
| static void update_and_free_page(struct hstate *h, struct page *page, |
| bool atomic) |
| { |
| if (!HPageVmemmapOptimized(page) || !atomic) { |
| __update_and_free_page(h, page); |
| return; |
| } |
| |
| /* |
| * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap pages. |
| * |
| * 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); |
| } |
| |
| static void update_and_free_pages_bulk(struct hstate *h, struct list_head *list) |
| { |
| struct page *page, *t_page; |
| |
| list_for_each_entry_safe(page, t_page, list, lru) { |
| update_and_free_page(h, page, false); |
| cond_resched(); |
| } |
| } |
| |
| 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; |
| } |
| |
| 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 = hugetlb_page_subpool(page); |
| bool restore_reserve; |
| unsigned long flags; |
| |
| VM_BUG_ON_PAGE(page_count(page), page); |
| VM_BUG_ON_PAGE(page_mapcount(page), page); |
| |
| hugetlb_set_page_subpool(page, NULL); |
| page->mapping = NULL; |
| restore_reserve = HPageRestoreReserve(page); |
| ClearHPageRestoreReserve(page); |
| |
| /* |
| * If HPageRestoreReserve 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 |
| * reservation, 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_irqsave(&hugetlb_lock, flags); |
| ClearHPageMigratable(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 (HPageTemporary(page)) { |
| remove_hugetlb_page(h, page, false); |
| spin_unlock_irqrestore(&hugetlb_lock, flags); |
| update_and_free_page(h, page, true); |
| } else if (h->surplus_huge_pages_node[nid]) { |
| /* remove the page from active list */ |
| remove_hugetlb_page(h, page, true); |
| spin_unlock_irqrestore(&hugetlb_lock, flags); |
| update_and_free_page(h, page, true); |
| } else { |
| arch_clear_hugepage_flags(page); |
| enqueue_huge_page(h, page); |
| spin_unlock_irqrestore(&hugetlb_lock, flags); |
| } |
| } |
| |
| /* |
| * Must be called with the hugetlb lock held |
| */ |
| static void __prep_account_new_huge_page(struct hstate *h, int nid) |
| { |
| lockdep_assert_held(&hugetlb_lock); |
| h->nr_huge_pages++; |
| h->nr_huge_pages_node[nid]++; |
| } |
| |
| static void __prep_new_huge_page(struct hstate *h, struct page *page) |
| { |
| free_huge_page_vmemmap(h, page); |
| INIT_LIST_HEAD(&page->lru); |
| set_compound_page_dtor(page, HUGETLB_PAGE_DTOR); |
| hugetlb_set_page_subpool(page, NULL); |
| set_hugetlb_cgroup(page, NULL); |
| set_hugetlb_cgroup_rsvd(page, NULL); |
| } |
| |
| static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) |
| { |
| __prep_new_huge_page(h, page); |
| spin_lock_irq(&hugetlb_lock); |
| __prep_account_new_huge_page(h, nid); |
| spin_unlock_irq(&hugetlb_lock); |
| } |
| |
| static bool __prep_compound_gigantic_page(struct page *page, unsigned int order, |
| bool demote) |
| { |
| int i, j; |
| 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); |
| /* |
| * Subtle and very unlikely |
| * |
| * Gigantic 'page allocators' such as memblock or cma will |
| * return a set of pages with each page ref counted. We need |
| * to turn this set of pages into a compound page with tail |
| * page ref counts set to zero. Code such as speculative page |
| * cache adding could take a ref on a 'to be' tail page. |
| * We need to respect any increased ref count, and only set |
| * the ref count to zero if count is currently 1. If count |
| * is not 1, we return an error. An error return indicates |
| * the set of pages can not be converted to a gigantic page. |
| * The caller who allocated the pages should then discard the |
| * pages using the appropriate free interface. |
| * |
| * In the case of demote, the ref count will be zero. |
| */ |
| if (!demote) { |
| if (!page_ref_freeze(p, 1)) { |
| pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n"); |
| goto out_error; |
| } |
| } else { |
| VM_BUG_ON_PAGE(page_count(p), p); |
| } |
| set_compound_head(p, page); |
| } |
| atomic_set(compound_mapcount_ptr(page), -1); |
| atomic_set(compound_pincount_ptr(page), 0); |
| return true; |
| |
| out_error: |
| /* undo tail page modifications made above */ |
| p = page + 1; |
| for (j = 1; j < i; j++, p = mem_map_next(p, page, j)) { |
| clear_compound_head(p); |
| set_page_refcounted(p); |
| } |
| /* need to clear PG_reserved on remaining tail pages */ |
| for (; j < nr_pages; j++, p = mem_map_next(p, page, j)) |
| __ClearPageReserved(p); |
| set_compound_order(page, 0); |
| #ifdef CONFIG_64BIT |
| page[1].compound_nr = 0; |
| #endif |
| __ClearPageHead(page); |
| return false; |
| } |
| |
| static bool prep_compound_gigantic_page(struct page *page, unsigned int order) |
| { |
| return __prep_compound_gigantic_page(page, order, false); |
| } |
| |
| static bool prep_compound_gigantic_page_for_demote(struct page *page, |
| unsigned int order) |
| { |
| return __prep_compound_gigantic_page(page, order, true); |
| } |
| |
| /* |
| * 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; |
| } |
| EXPORT_SYMBOL_GPL(PageHeadHuge); |
| |
| /* |
| * 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(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; |
| bool retry = false; |
| |
| retry: |
| 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)) { |
| if (!prep_compound_gigantic_page(page, huge_page_order(h))) { |
| /* |
| * Rare failure to convert pages to compound page. |
| * Free pages and try again - ONCE! |
| */ |
| free_gigantic_page(page, huge_page_order(h)); |
| if (!retry) { |
| retry = true; |
| goto retry; |
| } |
| return NULL; |
| } |
| } |
| 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; |
| } |
| |
| /* |
| * Remove huge page from pool from next node to free. Attempt to keep |
| * persistent huge pages more or less balanced over allowed nodes. |
| * This routine only 'removes' the hugetlb page. The caller must make |
| * an additional call to free the page to low level allocators. |
| * Called with hugetlb_lock locked. |
| */ |
| static struct page *remove_pool_huge_page(struct hstate *h, |
| nodemask_t *nodes_allowed, |
| bool acct_surplus) |
| { |
| int nr_nodes, node; |
| struct page *page = NULL; |
| |
| lockdep_assert_held(&hugetlb_lock); |
| 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])) { |
| page = list_entry(h->hugepage_freelists[node].next, |
| struct page, lru); |
| remove_hugetlb_page(h, page, acct_surplus); |
| break; |
| } |
| } |
| |
| return page; |
| } |
| |
| /* |
| * 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: |
| * |
| * -ENOMEM: failed to allocate vmemmap pages to free the freed hugepages |
| * when the system is under memory pressure and the feature of |
| * freeing unused vmemmap pages associated with each hugetlb page |
| * is enabled. |
| * -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_irq(&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); |
| 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(!HPageFreed(head))) { |
| spin_unlock_irq(&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; |
| } |
| |
| remove_hugetlb_page(h, head, false); |
| h->max_huge_pages--; |
| spin_unlock_irq(&hugetlb_lock); |
| |
| /* |
| * Normally update_and_free_page will allocate required vmemmmap |
| * before freeing the page. update_and_free_page will fail to |
| * free the page if it can not allocate required vmemmap. We |
| * need to adjust max_huge_pages if the page is not freed. |
| * Attempt to allocate vmemmmap here so that we can take |
| * appropriate action on failure. |
| */ |
| rc = alloc_huge_page_vmemmap(h, head); |
| if (!rc) { |
| /* |
| * 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); |
| } |
| update_and_free_page(h, head, false); |
| } else { |
| spin_lock_irq(&hugetlb_lock); |
| add_hugetlb_page(h, head, false); |
| h->max_huge_pages++; |
| spin_unlock_irq(&hugetlb_lock); |
| } |
| |
| return rc; |
| } |
| out: |
| spin_unlock_irq(&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, bool zero_ref) |
| { |
| struct page *page = NULL; |
| bool retry = false; |
| |
| if (hstate_is_gigantic(h)) |
| return NULL; |
| |
| spin_lock_irq(&hugetlb_lock); |
| if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) |
| goto out_unlock; |
| spin_unlock_irq(&hugetlb_lock); |
| |
| retry: |
| page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL); |
| if (!page) |
| return NULL; |
| |
| spin_lock_irq(&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) { |
| SetHPageTemporary(page); |
| spin_unlock_irq(&hugetlb_lock); |
| put_page(page); |
| return NULL; |
| } |
| |
| if (zero_ref) { |
| /* |
| * Caller requires a page with zero ref count. |
| * We will drop ref count here. If someone else is holding |
| * a ref, the page will be freed when they drop it. Abuse |
| * temporary page flag to accomplish this. |
| */ |
| SetHPageTemporary(page); |
| if (!put_page_testzero(page)) { |
| /* |
| * Unexpected inflated ref count on freshly allocated |
| * huge. Retry once. |
| */ |
| pr_info("HugeTLB unexpected inflated ref count on freshly allocated page\n"); |
| spin_unlock_irq(&hugetlb_lock); |
| if (retry) |
| return NULL; |
| |
| retry = true; |
| goto retry; |
| } |
| ClearHPageTemporary(page); |
| } |
| |
| h->surplus_huge_pages++; |
| h->surplus_huge_pages_node[page_to_nid(page)]++; |
| |
| out_unlock: |
| spin_unlock_irq(&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 |
| */ |
| SetHPageTemporary(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 = NULL; |
| 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); |
| if (mpol_is_preferred_many(mpol)) { |
| gfp_t gfp = gfp_mask | __GFP_NOWARN; |
| |
| gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); |
| page = alloc_surplus_huge_page(h, gfp, nid, nodemask, false); |
| |
| /* Fallback to all nodes if page==NULL */ |
| nodemask = NULL; |
| } |
| |
| if (!page) |
| page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask, false); |
| 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_irq(&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_irq(&hugetlb_lock); |
| return page; |
| } |
| } |
| spin_unlock_irq(&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, long delta) |
| __must_hold(&hugetlb_lock) |
| { |
| struct list_head surplus_list; |
| struct page *page, *tmp; |
| int ret; |
| long i; |
| long needed, allocated; |
| bool alloc_ok = true; |
| |
| lockdep_assert_held(&hugetlb_lock); |
| 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_irq(&hugetlb_lock); |
| for (i = 0; i < needed; i++) { |
| page = alloc_surplus_huge_page(h, htlb_alloc_mask(h), |
| NUMA_NO_NODE, NULL, true); |
| 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_irq(&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; |
| /* Add the page to the hugetlb allocator */ |
| enqueue_huge_page(h, page); |
| } |
| free: |
| spin_unlock_irq(&hugetlb_lock); |
| |
| /* |
| * Free unnecessary surplus pages to the buddy allocator. |
| * Pages have no ref count, call free_huge_page directly. |
| */ |
| list_for_each_entry_safe(page, tmp, &surplus_list, lru) |
| free_huge_page(page); |
| spin_lock_irq(&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. |
| */ |
| static void return_unused_surplus_pages(struct hstate *h, |
| unsigned long unused_resv_pages) |
| { |
| unsigned long nr_pages; |
| struct page *page; |
| LIST_HEAD(page_list); |
| |
| lockdep_assert_held(&hugetlb_lock); |
| /* Uncommit the reservation */ |
| h->resv_huge_pages -= unused_resv_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. |
| * remove_pool_huge_page() will balance the freed pages across the |
| * on-line nodes with memory and will handle the hstate accounting. |
| */ |
| while (nr_pages--) { |
| page = remove_pool_huge_page(h, &node_states[N_MEMORY], 1); |
| if (!page) |
| goto out; |
| |
| list_add(&page->lru, &page_list); |
| } |
| |
| out: |
| spin_unlock_irq(&hugetlb_lock); |
| update_and_free_pages_bulk(h, &page_list); |
| spin_lock_irq(&hugetlb_lock); |
| } |
| |
| |
| /* |
| * 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. |
| * |
| * vma_del_reservation is used in error paths where an entry in the reserve |
| * map was created during huge page allocation and must be removed. 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, |
| VMA_DEL_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; |
| case VMA_DEL_RESV: |
| if (vma->vm_flags & VM_MAYSHARE) { |
| region_abort(resv, idx, idx + 1, 1); |
| ret = region_del(resv, idx, idx + 1); |
| } else { |
| 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; |
| default: |
| BUG(); |
| } |
| |
| if (vma->vm_flags & VM_MAYSHARE || mode == VMA_DEL_RESV) |
| return ret; |
| /* |
| * We know private mapping must have HPAGE_RESV_OWNER set. |
| * |
| * 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 > 0) |
| return 0; |
| if (ret == 0) |
| return 1; |
| return ret; |
| } |
| |
| 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); |
| } |
| |
| static long vma_del_reservation(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr) |
| { |
| return __vma_reservation_common(h, vma, addr, VMA_DEL_RESV); |
| } |
| |
| /* |
| * This routine is called to restore reservation information on error paths. |
| * It should ONLY be called for pages allocated via alloc_huge_page(), and |
| * the hugetlb mutex should remain held when calling this routine. |
| * |
| * It handles two specific cases: |
| * 1) A reservation was in place and the page consumed the reservation. |
| * HPageRestoreReserve is set in the page. |
| * 2) No reservation was in place for the page, so HPageRestoreReserve is |
| * not set. However, alloc_huge_page always updates the reserve map. |
| * |
| * In case 1, free_huge_page later in the error path will increment the |
| * global reserve count. But, free_huge_page does not have enough context |
| * to adjust the reservation map. This case deals primarily with private |
| * mappings. Adjust the reserve map here to be consistent with global |
| * reserve count adjustments to be made by free_huge_page. Make sure the |
| * reserve map indicates there is a reservation present. |
| * |
| * In case 2, simply undo reserve map modifications done by alloc_huge_page. |
| */ |
| void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma, |
| unsigned long address, struct page *page) |
| { |
| long rc = vma_needs_reservation(h, vma, address); |
| |
| if (HPageRestoreReserve(page)) { |
| if (unlikely(rc < 0)) |
| /* |
| * Rare out of memory condition in reserve map |
| * manipulation. Clear HPageRestoreReserve 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. |
| */ |
| ClearHPageRestoreReserve(page); |
| else if (rc) |
| (void)vma_add_reservation(h, vma, address); |
| else |
| vma_end_reservation(h, vma, address); |
| } else { |
| if (!rc) { |
| /* |
| * This indicates there is an entry in the reserve map |
| * not added by alloc_huge_page. We know it was added |
| * before the alloc_huge_page call, otherwise |
| * HPageRestoreReserve would be set on the page. |
| * Remove the entry so that a subsequent allocation |
| * does not consume a reservation. |
| */ |
| rc = vma_del_reservation(h, vma, address); |
| if (rc < 0) |
| /* |
| * VERY rare out of memory condition. Since |
| * we can not delete the entry, set |
| * HPageRestoreReserve so that the reserve |
| * count will be incremented when the page |
| * is freed. This reserve will be consumed |
| * on a subsequent allocation. |
| */ |
| SetHPageRestoreReserve(page); |
| } else if (rc < 0) { |
| /* |
| * Rare out of memory condition from |
| * vma_needs_reservation call. Memory allocation is |
| * only attempted if a new entry is needed. Therefore, |
| * this implies there is not an entry in the |
| * reserve map. |
| * |
| * For shared mappings, no entry in the map indicates |
| * no reservation. We are done. |
| */ |
| if (!(vma->vm_flags & VM_MAYSHARE)) |
| /* |
| * For private mappings, no entry indicates |
| * a reservation is present. Since we can |
| * not add an entry, set SetHPageRestoreReserve |
| * on the page so reserve count will be |
| * incremented when freed. This reserve will |
| * be consumed on a subsequent allocation. |
| */ |
| SetHPageRestoreReserve(page); |
| } else |
| /* |
| * No reservation present, do nothing |
| */ |
| vma_end_reservation(h, vma, address); |
| } |
| } |
| |
| /* |
| * alloc_and_dissolve_huge_page - Allocate a new page and dissolve the old one |
| * @h: struct hstate old page belongs to |
| * @old_page: Old page to dissolve |
| * @list: List to isolate the page in case we need to |
| * Returns 0 on success, otherwise negated error. |
| */ |
| static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page, |
| struct list_head *list) |
| { |
| gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; |
| int nid = page_to_nid(old_page); |
| bool alloc_retry = false; |
| struct page *new_page; |
| int ret = 0; |
| |
| /* |
| * Before dissolving the page, we need to allocate a new one for the |
| * pool to remain stable. Here, we allocate the page and 'prep' it |
| * by doing everything but actually updating counters and adding to |
| * the pool. This simplifies and let us do most of the processing |
| * under the lock. |
| */ |
| alloc_retry: |
| new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL); |
| if (!new_page) |
| return -ENOMEM; |
| /* |
| * If all goes well, this page will be directly added to the free |
| * list in the pool. For this the ref count needs to be zero. |
| * Attempt to drop now, and retry once if needed. It is VERY |
| * unlikely there is another ref on the page. |
| * |
| * If someone else has a reference to the page, it will be freed |
| * when they drop their ref. Abuse temporary page flag to accomplish |
| * this. Retry once if there is an inflated ref count. |
| */ |
| SetHPageTemporary(new_page); |
| if (!put_page_testzero(new_page)) { |
| if (alloc_retry) |
| return -EBUSY; |
| |
| alloc_retry = true; |
| goto alloc_retry; |
| } |
| ClearHPageTemporary(new_page); |
| |
| __prep_new_huge_page(h, new_page); |
| |
| retry: |
| spin_lock_irq(&hugetlb_lock); |
| if (!PageHuge(old_page)) { |
| /* |
| * Freed from under us. Drop new_page too. |
| */ |
| goto free_new; |
| } else if (page_count(old_page)) { |
| /* |
| * Someone has grabbed the page, try to isolate it here. |
| * Fail with -EBUSY if not possible. |
| */ |
| spin_unlock_irq(&hugetlb_lock); |
| if (!isolate_huge_page(old_page, list)) |
| ret = -EBUSY; |
| spin_lock_irq(&hugetlb_lock); |
| goto free_new; |
| } else if (!HPageFreed(old_page)) { |
| /* |
| * Page's refcount is 0 but it has not been enqueued in the |
| * freelist yet. Race window is small, so we can succeed here if |
| * we retry. |
| */ |
| spin_unlock_irq(&hugetlb_lock); |
| cond_resched(); |
| goto retry; |
| } else { |
| /* |
| * Ok, old_page is still a genuine free hugepage. Remove it from |
| * the freelist and decrease the counters. These will be |
| * incremented again when calling __prep_account_new_huge_page() |
| * and enqueue_huge_page() for new_page. The counters will remain |
| * stable since this happens under the lock. |
| */ |
| remove_hugetlb_page(h, old_page, false); |
| |
| /* |
| * Ref count on new page is already zero as it was dropped |
| * earlier. It can be directly added to the pool free list. |
| */ |
| __prep_account_new_huge_page(h, nid); |
| enqueue_huge_page(h, new_page); |
| |
| /* |
| * Pages have been replaced, we can safely free the old one. |
| */ |
| spin_unlock_irq(&hugetlb_lock); |
| update_and_free_page(h, old_page, false); |
| } |
| |
| return ret; |
| |
| free_new: |
| spin_unlock_irq(&hugetlb_lock); |
| /* Page has a zero ref count, but needs a ref to be freed */ |
| set_page_refcounted(new_page); |
| update_and_free_page(h, new_page, false); |
| |
| return ret; |
| } |
| |
| int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list) |
| { |
| struct hstate *h; |
| struct page *head; |
| int ret = -EBUSY; |
| |
| /* |
| * The page might have been dissolved from under our feet, so make sure |
| * to carefully check the state under the lock. |
| * Return success when racing as if we dissolved the page ourselves. |
| */ |
| spin_lock_irq(&hugetlb_lock); |
| if (PageHuge(page)) { |
| head = compound_head(page); |
| h = page_hstate(head); |
| } else { |
| spin_unlock_irq(&hugetlb_lock); |
| return 0; |
| } |
| spin_unlock_irq(&hugetlb_lock); |
| |
| /* |
| * Fence off gigantic pages as there is a cyclic dependency between |
| * alloc_contig_range and them. Return -ENOMEM as this has the effect |
| * of bailing out right away without further retrying. |
| */ |
| if (hstate_is_gigantic(h)) |
| return -ENOMEM; |
| |
| if (page_count(head) && isolate_huge_page(head, list)) |
| ret = 0; |
| else if (!page_count(head)) |
| ret = alloc_and_dissolve_huge_page(h, head, list); |
| |
| return ret; |
| } |
| |
| 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; |
| 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_irq(&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_irq(&hugetlb_lock); |
| page = alloc_buddy_huge_page_with_mpol(h, vma, addr); |
| if (!page) |
| goto out_uncharge_cgroup; |
| if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { |
| SetHPageRestoreReserve(page); |
| h->resv_huge_pages--; |
| } |
| spin_lock_irq(&hugetlb_lock); |
| 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_irq(&hugetlb_lock); |
| |
| hugetlb_set_page_subpool(page, 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, int nid) |
| __attribute__ ((weak, alias("__alloc_bootmem_huge_page"))); |
| int __alloc_bootmem_huge_page(struct hstate *h, int nid) |
| { |
| struct huge_bootmem_page *m = NULL; /* initialize for clang */ |
| int nr_nodes, node; |
| |
| if (nid != NUMA_NO_NODE && nid >= nr_online_nodes) |
| return 0; |
| /* do node specific alloc */ |
| if (nid != NUMA_NO_NODE) { |
| m = memblock_alloc_try_nid_raw(huge_page_size(h), huge_page_size(h), |
| 0, MEMBLOCK_ALLOC_ACCESSIBLE, nid); |
| if (!m) |
| return 0; |
| goto found; |
| } |
| /* allocate from next node when distributing huge pages */ |
| for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { |
| m = memblock_alloc_try_nid_raw( |
| huge_page_size(h), huge_page_size(h), |
| 0, MEMBLOCK_ALLOC_ACCESSIBLE, node); |
| /* |
| * Use the beginning of the huge page to store the |
| * huge_bootmem_page struct (until gather_bootmem |
| * puts them into the mem_map). |
| */ |
| if (!m) |
| return 0; |
| goto found; |
| } |
| |
| found: |
| /* 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); |
| if (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); /* add to the hugepage allocator */ |
| } else { |
| /* VERY unlikely inflated ref count on a tail page */ |
| free_gigantic_page(page, huge_page_order(h)); |
| } |
| |
| /* |
| * 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_onenode(struct hstate *h, int nid) |
| { |
| unsigned long i; |
| char buf[32]; |
| |
| for (i = 0; i < h->max_huge_pages_node[nid]; ++i) { |
| if (hstate_is_gigantic(h)) { |
| if (!alloc_bootmem_huge_page(h, nid)) |
| break; |
| } else { |
| struct page *page; |
| gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; |
| |
| page = alloc_fresh_huge_page(h, gfp_mask, nid, |
| &node_states[N_MEMORY], NULL); |
| if (!page) |
| break; |
| put_page(page); /* free it into the hugepage allocator */ |
| } |
| cond_resched(); |
| } |
| if (i == h->max_huge_pages_node[nid]) |
| return; |
| |
| string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); |
| pr_warn("HugeTLB: allocating %u of page size %s failed node%d. Only allocated %lu hugepages.\n", |
| h->max_huge_pages_node[nid], buf, nid, i); |
| h->max_huge_pages -= (h->max_huge_pages_node[nid] - i); |
| h->max_huge_pages_node[nid] = i; |
| } |
| |
| static void __init hugetlb_hstate_alloc_pages(struct hstate *h) |
| { |
| unsigned long i; |
| nodemask_t *node_alloc_noretry; |
| bool node_specific_alloc = false; |
| |
| /* skip gigantic hugepages allocation if hugetlb_cma enabled */ |
| if (hstate_is_gigantic(h) && hugetlb_cma_size) { |
| pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n"); |
| return; |
| } |
| |
| /* do node specific alloc */ |
| for (i = 0; i < nr_online_nodes; i++) { |
| if (h->max_huge_pages_node[i] > 0) { |
| hugetlb_hstate_alloc_pages_onenode(h, i); |
| node_specific_alloc = true; |
| } |
| } |
| |
| if (node_specific_alloc) |
| return; |
| |
| /* below will do all node balanced alloc */ |
| 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 (!alloc_bootmem_huge_page(h, NUMA_NO_NODE)) |
| 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; |
| } |
| kfree(node_alloc_noretry); |
| } |
| |
| static void __init hugetlb_init_hstates(void) |
| { |
| struct hstate *h, *h2; |
| |
| 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); |
| |
| /* |
| * Set demote order for each hstate. Note that |
| * h->demote_order is initially 0. |
| * - We can not demote gigantic pages if runtime freeing |
| * is not supported, so skip this. |
| * - If CMA allocation is possible, we can not demote |
| * HUGETLB_PAGE_ORDER or smaller size pages. |
| */ |
| if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) |
| continue; |
| if (hugetlb_cma_size && h->order <= HUGETLB_PAGE_ORDER) |
| continue; |
| for_each_hstate(h2) { |
| if (h2 == h) |
| continue; |
| if (h2->order < h->order && |
| h2->order > h->demote_order) |
| h->demote_order = h2->order; |
| } |
| } |
| 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; |
| LIST_HEAD(page_list); |
| |
| lockdep_assert_held(&hugetlb_lock); |
| if (hstate_is_gigantic(h)) |
| return; |
| |
| /* |
| * Collect pages to be freed on a list, and free after dropping lock |
| */ |
| 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) |
| goto out; |
| if (PageHighMem(page)) |
| continue; |
| remove_hugetlb_page(h, page, false); |
| list_add(&page->lru, &page_list); |
| } |
| } |
| |
| out: |
| spin_unlock_irq(&hugetlb_lock); |
| update_and_free_pages_bulk(h, &page_list); |
| spin_lock_irq(&hugetlb_lock); |
| } |
| #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; |
| |
| lockdep_assert_held(&hugetlb_lock); |
| 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; |
| struct page *page; |
| LIST_HEAD(page_list); |
| 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. |
|