diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 3743 |
1 files changed, 3118 insertions, 625 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 51c9e2c0164..7a0a73d2fcf 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1,252 +1,1110 @@ /* * Generic hugetlb support. - * (C) William Irwin, April 2004 + * (C) Nadia Yvette Chambers, April 2004 */ -#include <linux/gfp.h> #include <linux/list.h> #include <linux/init.h> #include <linux/module.h> #include <linux/mm.h> +#include <linux/seq_file.h> #include <linux/sysctl.h> #include <linux/highmem.h> +#include <linux/mmu_notifier.h> #include <linux/nodemask.h> #include <linux/pagemap.h> #include <linux/mempolicy.h> +#include <linux/compiler.h> #include <linux/cpuset.h> #include <linux/mutex.h> +#include <linux/bootmem.h> +#include <linux/sysfs.h> +#include <linux/slab.h> +#include <linux/rmap.h> +#include <linux/swap.h> +#include <linux/swapops.h> +#include <linux/page-isolation.h> +#include <linux/jhash.h> #include <asm/page.h> #include <asm/pgtable.h> +#include <asm/tlb.h> +#include <linux/io.h> #include <linux/hugetlb.h> +#include <linux/hugetlb_cgroup.h> +#include <linux/node.h> #include "internal.h" const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; -static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages; -static unsigned long surplus_huge_pages; -static unsigned long nr_overcommit_huge_pages; -unsigned long max_huge_pages; -unsigned long sysctl_overcommit_huge_pages; -static struct list_head hugepage_freelists[MAX_NUMNODES]; -static unsigned int nr_huge_pages_node[MAX_NUMNODES]; -static unsigned int free_huge_pages_node[MAX_NUMNODES]; -static unsigned int surplus_huge_pages_node[MAX_NUMNODES]; -static gfp_t htlb_alloc_mask = GFP_HIGHUSER; unsigned long hugepages_treat_as_movable; -static int hugetlb_next_nid; + +int hugetlb_max_hstate __read_mostly; +unsigned int default_hstate_idx; +struct hstate hstates[HUGE_MAX_HSTATE]; + +__initdata LIST_HEAD(huge_boot_pages); + +/* for command line parsing */ +static struct hstate * __initdata parsed_hstate; +static unsigned long __initdata default_hstate_max_huge_pages; +static unsigned long __initdata default_hstate_size; + +/* + * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages, + * free_huge_pages, and surplus_huge_pages. + */ +DEFINE_SPINLOCK(hugetlb_lock); /* - * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages + * Serializes faults on the same logical page. This is used to + * prevent spurious OOMs when the hugepage pool is fully utilized. */ -static DEFINE_SPINLOCK(hugetlb_lock); +static int num_fault_mutexes; +static struct mutex *htlb_fault_mutex_table ____cacheline_aligned_in_smp; -static void clear_huge_page(struct page *page, unsigned long addr) +static inline void unlock_or_release_subpool(struct hugepage_subpool *spool) { - int i; + bool free = (spool->count == 0) && (spool->used_hpages == 0); + + spin_unlock(&spool->lock); + + /* If no pages are used, and no other handles to the subpool + * remain, free the subpool the subpool remain */ + if (free) + kfree(spool); +} + +struct hugepage_subpool *hugepage_new_subpool(long nr_blocks) +{ + struct hugepage_subpool *spool; + + spool = kmalloc(sizeof(*spool), GFP_KERNEL); + if (!spool) + return NULL; + + spin_lock_init(&spool->lock); + spool->count = 1; + spool->max_hpages = nr_blocks; + spool->used_hpages = 0; + + return spool; +} + +void hugepage_put_subpool(struct hugepage_subpool *spool) +{ + spin_lock(&spool->lock); + BUG_ON(!spool->count); + spool->count--; + unlock_or_release_subpool(spool); +} + +static int hugepage_subpool_get_pages(struct hugepage_subpool *spool, + long delta) +{ + int ret = 0; + + if (!spool) + return 0; - might_sleep(); - for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) { - cond_resched(); - clear_user_highpage(page + i, addr + i * PAGE_SIZE); + spin_lock(&spool->lock); + if ((spool->used_hpages + delta) <= spool->max_hpages) { + spool->used_hpages += delta; + } else { + ret = -ENOMEM; } + spin_unlock(&spool->lock); + + return ret; } -static void copy_huge_page(struct page *dst, struct page *src, - unsigned long addr, struct vm_area_struct *vma) +static void hugepage_subpool_put_pages(struct hugepage_subpool *spool, + long delta) { - int i; + if (!spool) + return; + + spin_lock(&spool->lock); + spool->used_hpages -= delta; + /* If hugetlbfs_put_super couldn't free spool due to + * an outstanding quota reference, free it now. */ + unlock_or_release_subpool(spool); +} + +static inline struct hugepage_subpool *subpool_inode(struct inode *inode) +{ + return HUGETLBFS_SB(inode->i_sb)->spool; +} + +static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) +{ + return subpool_inode(file_inode(vma->vm_file)); +} + +/* + * Region tracking -- allows tracking of reservations and instantiated pages + * across the pages in a mapping. + * + * The region data structures are embedded into a resv_map and + * protected by a resv_map's lock + */ +struct file_region { + struct list_head link; + long from; + long to; +}; + +static long region_add(struct resv_map *resv, long f, long t) +{ + struct list_head *head = &resv->regions; + struct file_region *rg, *nrg, *trg; + + spin_lock(&resv->lock); + /* Locate the region we are either in or before. */ + list_for_each_entry(rg, head, link) + if (f <= rg->to) + break; + + /* Round our left edge to the current segment if it encloses us. */ + if (f > rg->from) + f = rg->from; + + /* Check for and consume any regions we now overlap with. */ + nrg = rg; + list_for_each_entry_safe(rg, trg, rg->link.prev, link) { + if (&rg->link == head) + break; + if (rg->from > t) + break; - might_sleep(); - for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) { - cond_resched(); - copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); + /* If this area reaches higher then extend our area to + * include it completely. If this is not the first area + * which we intend to reuse, free it. */ + if (rg->to > t) + t = rg->to; + if (rg != nrg) { + list_del(&rg->link); + kfree(rg); + } } + nrg->from = f; + nrg->to = t; + spin_unlock(&resv->lock); + return 0; } -static void enqueue_huge_page(struct page *page) +static long region_chg(struct resv_map *resv, long f, long t) +{ + struct list_head *head = &resv->regions; + struct file_region *rg, *nrg = NULL; + long chg = 0; + +retry: + spin_lock(&resv->lock); + /* Locate the region we are before or in. */ + list_for_each_entry(rg, head, link) + if (f <= rg->to) + break; + + /* If we are below the current region then a new region is required. + * Subtle, allocate a new region at the position but make it zero + * size such that we can guarantee to record the reservation. */ + if (&rg->link == head || t < rg->from) { + if (!nrg) { + spin_unlock(&resv->lock); + nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); + if (!nrg) + return -ENOMEM; + + nrg->from = f; + nrg->to = f; + INIT_LIST_HEAD(&nrg->link); + goto retry; + } + + list_add(&nrg->link, rg->link.prev); + chg = t - f; + goto out_nrg; + } + + /* Round our left edge to the current segment if it encloses us. */ + if (f > rg->from) + f = rg->from; + chg = t - f; + + /* Check for and consume any regions we now overlap with. */ + list_for_each_entry(rg, rg->link.prev, link) { + if (&rg->link == head) + break; + if (rg->from > t) + goto out; + + /* We overlap with this area, if it extends further than + * us then we must extend ourselves. Account for its + * existing reservation. */ + if (rg->to > t) { + chg += rg->to - t; + t = rg->to; + } + chg -= rg->to - rg->from; + } + +out: + spin_unlock(&resv->lock); + /* We already know we raced and no longer need the new region */ + kfree(nrg); + return chg; +out_nrg: + spin_unlock(&resv->lock); + return chg; +} + +static long region_truncate(struct resv_map *resv, long end) +{ + struct list_head *head = &resv->regions; + struct file_region *rg, *trg; + long chg = 0; + + spin_lock(&resv->lock); + /* Locate the region we are either in or before. */ + list_for_each_entry(rg, head, link) + if (end <= rg->to) + break; + if (&rg->link == head) + goto out; + + /* If we are in the middle of a region then adjust it. */ + if (end > rg->from) { + chg = rg->to - end; + rg->to = end; + rg = list_entry(rg->link.next, typeof(*rg), link); + } + + /* Drop any remaining regions. */ + list_for_each_entry_safe(rg, trg, rg->link.prev, link) { + if (&rg->link == head) + break; + chg += rg->to - rg->from; + list_del(&rg->link); + kfree(rg); + } + +out: + spin_unlock(&resv->lock); + return chg; +} + +static long region_count(struct resv_map *resv, long f, long t) +{ + struct list_head *head = &resv->regions; + struct file_region *rg; + long chg = 0; + + spin_lock(&resv->lock); + /* Locate each segment we overlap with, and count that overlap. */ + list_for_each_entry(rg, head, link) { + long seg_from; + long seg_to; + + if (rg->to <= f) + continue; + if (rg->from >= t) + break; + + seg_from = max(rg->from, f); + seg_to = min(rg->to, t); + + chg += seg_to - seg_from; + } + spin_unlock(&resv->lock); + + return chg; +} + +/* + * Convert the address within this vma to the page offset within + * the mapping, in pagecache page units; huge pages here. + */ +static pgoff_t vma_hugecache_offset(struct hstate *h, + struct vm_area_struct *vma, unsigned long address) +{ + return ((address - vma->vm_start) >> huge_page_shift(h)) + + (vma->vm_pgoff >> huge_page_order(h)); +} + +pgoff_t linear_hugepage_index(struct vm_area_struct *vma, + unsigned long address) +{ + return vma_hugecache_offset(hstate_vma(vma), vma, address); +} + +/* + * Return the size of the pages allocated when backing a VMA. In the majority + * cases this will be same size as used by the page table entries. + */ +unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) +{ + struct hstate *hstate; + + if (!is_vm_hugetlb_page(vma)) + return PAGE_SIZE; + + hstate = hstate_vma(vma); + + return 1UL << huge_page_shift(hstate); +} +EXPORT_SYMBOL_GPL(vma_kernel_pagesize); + +/* + * Return the page size being used by the MMU to back a VMA. In the majority + * of cases, the page size used by the kernel matches the MMU size. On + * architectures where it differs, an architecture-specific version of this + * function is required. + */ +#ifndef vma_mmu_pagesize +unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) +{ + return vma_kernel_pagesize(vma); +} +#endif + +/* + * Flags for MAP_PRIVATE reservations. These are stored in the bottom + * bits of the reservation map pointer, which are always clear due to + * alignment. + */ +#define HPAGE_RESV_OWNER (1UL << 0) +#define HPAGE_RESV_UNMAPPED (1UL << 1) +#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) + +/* + * These helpers are used to track how many pages are reserved for + * faults in a MAP_PRIVATE mapping. Only the process that called mmap() + * is guaranteed to have their future faults succeed. + * + * With the exception of reset_vma_resv_huge_pages() which is called at fork(), + * the reserve counters are updated with the hugetlb_lock held. It is safe + * to reset the VMA at fork() time as it is not in use yet and there is no + * chance of the global counters getting corrupted as a result of the values. + * + * The private mapping reservation is represented in a subtly different + * manner to a shared mapping. A shared mapping has a region map associated + * with the underlying file, this region map represents the backing file + * pages which have ever had a reservation assigned which this persists even + * after the page is instantiated. A private mapping has a region map + * associated with the original mmap which is attached to all VMAs which + * reference it, this region map represents those offsets which have consumed + * reservation ie. where pages have been instantiated. + */ +static unsigned long get_vma_private_data(struct vm_area_struct *vma) +{ + return (unsigned long)vma->vm_private_data; +} + +static void set_vma_private_data(struct vm_area_struct *vma, + unsigned long value) +{ + vma->vm_private_data = (void *)value; +} + +struct resv_map *resv_map_alloc(void) +{ + struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); + if (!resv_map) + return NULL; + + kref_init(&resv_map->refs); + spin_lock_init(&resv_map->lock); + INIT_LIST_HEAD(&resv_map->regions); + + return resv_map; +} + +void resv_map_release(struct kref *ref) +{ + struct resv_map *resv_map = container_of(ref, struct resv_map, refs); + + /* Clear out any active regions before we release the map. */ + region_truncate(resv_map, 0); + kfree(resv_map); +} + +static inline struct resv_map *inode_resv_map(struct inode *inode) +{ + return inode->i_mapping->private_data; +} + +static struct resv_map *vma_resv_map(struct vm_area_struct *vma) +{ + VM_BUG_ON(!is_vm_hugetlb_page(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(!is_vm_hugetlb_page(vma)); + VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); + + set_vma_private_data(vma, (get_vma_private_data(vma) & + HPAGE_RESV_MASK) | (unsigned long)map); +} + +static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) +{ + VM_BUG_ON(!is_vm_hugetlb_page(vma)); + VM_BUG_ON(vma->vm_flags & VM_MAYSHARE); + + set_vma_private_data(vma, get_vma_private_data(vma) | flags); +} + +static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) +{ + VM_BUG_ON(!is_vm_hugetlb_page(vma)); + + return (get_vma_private_data(vma) & flag) != 0; +} + +/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ +void reset_vma_resv_huge_pages(struct vm_area_struct *vma) +{ + VM_BUG_ON(!is_vm_hugetlb_page(vma)); + if (!(vma->vm_flags & VM_MAYSHARE)) + vma->vm_private_data = (void *)0; +} + +/* Returns true if the VMA has associated reserve pages */ +static int vma_has_reserves(struct vm_area_struct *vma, long chg) +{ + if (vma->vm_flags & VM_NORESERVE) { + /* + * This address is already reserved by other process(chg == 0), + * so, we should decrement reserved count. Without decrementing, + * reserve count remains after releasing inode, because this + * allocated page will go into page cache and is regarded as + * coming from reserved pool in releasing step. Currently, we + * don't have any other solution to deal with this situation + * properly, so add work-around here. + */ + if (vma->vm_flags & VM_MAYSHARE && chg == 0) + return 1; + else + return 0; + } + + /* Shared mappings always use reserves */ + if (vma->vm_flags & VM_MAYSHARE) + return 1; + + /* + * Only the process that called mmap() has reserves for + * private mappings. + */ + if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) + return 1; + + return 0; +} + +static void enqueue_huge_page(struct hstate *h, struct page *page) { int nid = page_to_nid(page); - list_add(&page->lru, &hugepage_freelists[nid]); - free_huge_pages++; - free_huge_pages_node[nid]++; + list_move(&page->lru, &h->hugepage_freelists[nid]); + h->free_huge_pages++; + h->free_huge_pages_node[nid]++; } -static struct page *dequeue_huge_page(void) +static struct page *dequeue_huge_page_node(struct hstate *h, int nid) { - int nid; - struct page *page = NULL; + struct page *page; - for (nid = 0; nid < MAX_NUMNODES; ++nid) { - if (!list_empty(&hugepage_freelists[nid])) { - page = list_entry(hugepage_freelists[nid].next, - struct page, lru); - list_del(&page->lru); - free_huge_pages--; - free_huge_pages_node[nid]--; + list_for_each_entry(page, &h->hugepage_freelists[nid], lru) + if (!is_migrate_isolate_page(page)) break; + /* + * if 'non-isolated free hugepage' not found on the list, + * the allocation fails. + */ + if (&h->hugepage_freelists[nid] == &page->lru) + return NULL; + list_move(&page->lru, &h->hugepage_activelist); + set_page_refcounted(page); + h->free_huge_pages--; + h->free_huge_pages_node[nid]--; + return page; +} + +/* Movability of hugepages depends on migration support. */ +static inline gfp_t htlb_alloc_mask(struct hstate *h) +{ + if (hugepages_treat_as_movable || hugepage_migration_supported(h)) + return GFP_HIGHUSER_MOVABLE; + else + return GFP_HIGHUSER; +} + +static struct page *dequeue_huge_page_vma(struct hstate *h, + struct vm_area_struct *vma, + unsigned long address, int avoid_reserve, + long chg) +{ + struct page *page = NULL; + struct mempolicy *mpol; + nodemask_t *nodemask; + struct zonelist *zonelist; + struct zone *zone; + struct zoneref *z; + unsigned int cpuset_mems_cookie; + + /* + * A child process with MAP_PRIVATE mappings created by their parent + * have no page reserves. This check ensures that reservations are + * not "stolen". The child may still get SIGKILLed + */ + if (!vma_has_reserves(vma, chg) && + h->free_huge_pages - h->resv_huge_pages == 0) + goto err; + + /* If reserves cannot be used, ensure enough pages are in the pool */ + if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) + goto err; + +retry_cpuset: + cpuset_mems_cookie = read_mems_allowed_begin(); + zonelist = huge_zonelist(vma, address, + htlb_alloc_mask(h), &mpol, &nodemask); + + for_each_zone_zonelist_nodemask(zone, z, zonelist, + MAX_NR_ZONES - 1, nodemask) { + if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask(h))) { + page = dequeue_huge_page_node(h, zone_to_nid(zone)); + if (page) { + if (avoid_reserve) + break; + if (!vma_has_reserves(vma, chg)) + break; + + SetPagePrivate(page); + h->resv_huge_pages--; + break; + } } } + + mpol_cond_put(mpol); + if (unlikely(!page && read_mems_allowed_retry(cpuset_mems_cookie))) + goto retry_cpuset; return page; + +err: + return NULL; +} + +/* + * common helper functions for hstate_next_node_to_{alloc|free}. + * We may have allocated or freed a huge page based on a different + * nodes_allowed previously, so h->next_node_to_{alloc|free} might + * be outside of *nodes_allowed. Ensure that we use an allowed + * node for alloc or free. + */ +static int next_node_allowed(int nid, nodemask_t *nodes_allowed) +{ + nid = next_node(nid, *nodes_allowed); + if (nid == MAX_NUMNODES) + nid = first_node(*nodes_allowed); + VM_BUG_ON(nid >= MAX_NUMNODES); + + return nid; } -static struct page *dequeue_huge_page_vma(struct vm_area_struct *vma, - unsigned long address) +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; - struct page *page = NULL; - struct mempolicy *mpol; - struct zonelist *zonelist = huge_zonelist(vma, address, - htlb_alloc_mask, &mpol); - struct zone **z; - - for (z = zonelist->zones; *z; z++) { - nid = zone_to_nid(*z); - if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) && - !list_empty(&hugepage_freelists[nid])) { - page = list_entry(hugepage_freelists[nid].next, - struct page, lru); - list_del(&page->lru); - free_huge_pages--; - free_huge_pages_node[nid]--; - if (vma && vma->vm_flags & VM_MAYSHARE) - resv_huge_pages--; - break; + + VM_BUG_ON(!nodes_allowed); + + nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); + h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); + + return nid; +} + +/* + * helper for free_pool_huge_page() - return the previously saved + * node ["this node"] from which to free a huge page. Advance the + * next node id whether or not we find a free huge page to free so + * that the next attempt to free addresses the next node. + */ +static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) +{ + int nid; + + VM_BUG_ON(!nodes_allowed); + + nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); + h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); + + return nid; +} + +#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ + for (nr_nodes = nodes_weight(*mask); \ + nr_nodes > 0 && \ + ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ + nr_nodes--) + +#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ + for (nr_nodes = nodes_weight(*mask); \ + nr_nodes > 0 && \ + ((node = hstate_next_node_to_free(hs, mask)) || 1); \ + nr_nodes--) + +#if defined(CONFIG_CMA) && defined(CONFIG_X86_64) +static void destroy_compound_gigantic_page(struct page *page, + unsigned long order) +{ + int i; + int nr_pages = 1 << order; + struct page *p = page + 1; + + for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { + __ClearPageTail(p); + set_page_refcounted(p); + p->first_page = NULL; + } + + set_compound_order(page, 0); + __ClearPageHead(page); +} + +static void free_gigantic_page(struct page *page, unsigned order) +{ + free_contig_range(page_to_pfn(page), 1 << order); +} + +static int __alloc_gigantic_page(unsigned long start_pfn, + unsigned long nr_pages) +{ + unsigned long end_pfn = start_pfn + nr_pages; + return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE); +} + +static bool pfn_range_valid_gigantic(unsigned long start_pfn, + unsigned long nr_pages) +{ + unsigned long i, end_pfn = start_pfn + nr_pages; + struct page *page; + + for (i = start_pfn; i < end_pfn; i++) { + if (!pfn_valid(i)) + return false; + + page = pfn_to_page(i); + + if (PageReserved(page)) + return false; + + if (page_count(page) > 0) + return false; + + if (PageHuge(page)) + return false; + } + + return true; +} + +static bool zone_spans_last_pfn(const struct zone *zone, + unsigned long start_pfn, unsigned long nr_pages) +{ + unsigned long last_pfn = start_pfn + nr_pages - 1; + return zone_spans_pfn(zone, last_pfn); +} + +static struct page *alloc_gigantic_page(int nid, unsigned order) +{ + unsigned long nr_pages = 1 << order; + unsigned long ret, pfn, flags; + struct zone *z; + + z = NODE_DATA(nid)->node_zones; + for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) { + spin_lock_irqsave(&z->lock, flags); + + pfn = ALIGN(z->zone_start_pfn, nr_pages); + while (zone_spans_last_pfn(z, pfn, nr_pages)) { + if (pfn_range_valid_gigantic(pfn, nr_pages)) { + /* + * We release the zone lock here because + * alloc_contig_range() will also lock the zone + * at some point. If there's an allocation + * spinning on this lock, it may win the race + * and cause alloc_contig_range() to fail... + */ + spin_unlock_irqrestore(&z->lock, flags); + ret = __alloc_gigantic_page(pfn, nr_pages); + if (!ret) + return pfn_to_page(pfn); + spin_lock_irqsave(&z->lock, flags); + } + pfn += nr_pages; } + + spin_unlock_irqrestore(&z->lock, flags); } - mpol_free(mpol); /* unref if mpol !NULL */ + + return NULL; +} + +static void prep_new_huge_page(struct hstate *h, struct page *page, int nid); +static void prep_compound_gigantic_page(struct page *page, unsigned long order); + +static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid) +{ + struct page *page; + + page = alloc_gigantic_page(nid, huge_page_order(h)); + if (page) { + prep_compound_gigantic_page(page, huge_page_order(h)); + prep_new_huge_page(h, page, nid); + } + return page; } -static void update_and_free_page(struct page *page) +static int alloc_fresh_gigantic_page(struct hstate *h, + nodemask_t *nodes_allowed) +{ + struct page *page = NULL; + int nr_nodes, node; + + for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { + page = alloc_fresh_gigantic_page_node(h, node); + if (page) + return 1; + } + + return 0; +} + +static inline bool gigantic_page_supported(void) { return true; } +#else +static inline bool gigantic_page_supported(void) { return false; } +static inline void free_gigantic_page(struct page *page, unsigned order) { } +static inline void destroy_compound_gigantic_page(struct page *page, + unsigned long order) { } +static inline int alloc_fresh_gigantic_page(struct hstate *h, + nodemask_t *nodes_allowed) { return 0; } +#endif + +static void update_and_free_page(struct hstate *h, struct page *page) { int i; - nr_huge_pages--; - nr_huge_pages_node[page_to_nid(page)]--; - for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) { - page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | - 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | - 1 << PG_private | 1<< PG_writeback); + + if (hstate_is_gigantic(h) && !gigantic_page_supported()) + return; + + h->nr_huge_pages--; + h->nr_huge_pages_node[page_to_nid(page)]--; + for (i = 0; i < pages_per_huge_page(h); i++) { + page[i].flags &= ~(1 << PG_locked | 1 << PG_error | + 1 << PG_referenced | 1 << PG_dirty | + 1 << PG_active | 1 << PG_private | + 1 << PG_writeback); } + VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); set_compound_page_dtor(page, NULL); set_page_refcounted(page); - __free_pages(page, HUGETLB_PAGE_ORDER); + if (hstate_is_gigantic(h)) { + destroy_compound_gigantic_page(page, huge_page_order(h)); + free_gigantic_page(page, huge_page_order(h)); + } else { + arch_release_hugepage(page); + __free_pages(page, huge_page_order(h)); + } +} + +struct hstate *size_to_hstate(unsigned long size) +{ + struct hstate *h; + + for_each_hstate(h) { + if (huge_page_size(h) == size) + return h; + } + return NULL; } -static void free_huge_page(struct page *page) +void free_huge_page(struct page *page) { + /* + * Can't pass hstate in here because it is called from the + * compound page destructor. + */ + struct hstate *h = page_hstate(page); int nid = page_to_nid(page); - struct address_space *mapping; + struct hugepage_subpool *spool = + (struct hugepage_subpool *)page_private(page); + bool restore_reserve; - mapping = (struct address_space *) page_private(page); set_page_private(page, 0); + page->mapping = NULL; BUG_ON(page_count(page)); - INIT_LIST_HEAD(&page->lru); + BUG_ON(page_mapcount(page)); + restore_reserve = PagePrivate(page); + ClearPagePrivate(page); spin_lock(&hugetlb_lock); - if (surplus_huge_pages_node[nid]) { - update_and_free_page(page); - surplus_huge_pages--; - surplus_huge_pages_node[nid]--; + hugetlb_cgroup_uncharge_page(hstate_index(h), + pages_per_huge_page(h), page); + if (restore_reserve) + h->resv_huge_pages++; + + if (h->surplus_huge_pages_node[nid]) { + /* remove the page from active list */ + list_del(&page->lru); + update_and_free_page(h, page); + h->surplus_huge_pages--; + h->surplus_huge_pages_node[nid]--; } else { - enqueue_huge_page(page); + arch_clear_hugepage_flags(page); + enqueue_huge_page(h, page); } spin_unlock(&hugetlb_lock); - if (mapping) - hugetlb_put_quota(mapping, 1); + hugepage_subpool_put_pages(spool, 1); +} + +static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) +{ + INIT_LIST_HEAD(&page->lru); + set_compound_page_dtor(page, free_huge_page); + spin_lock(&hugetlb_lock); + set_hugetlb_cgroup(page, NULL); + h->nr_huge_pages++; + h->nr_huge_pages_node[nid]++; + spin_unlock(&hugetlb_lock); + put_page(page); /* free it into the hugepage allocator */ +} + +static void prep_compound_gigantic_page(struct page *page, unsigned long order) +{ + int i; + int nr_pages = 1 << order; + struct page *p = page + 1; + + /* we rely on prep_new_huge_page to set the destructor */ + set_compound_order(page, order); + __SetPageHead(page); + __ClearPageReserved(page); + for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { + __SetPageTail(p); + /* + * For gigantic hugepages allocated through bootmem at + * boot, it's safer to be consistent with the not-gigantic + * hugepages and clear the PG_reserved bit from all tail pages + * too. Otherwse drivers using get_user_pages() to access tail + * pages may get the reference counting wrong if they see + * PG_reserved set on a tail page (despite the head page not + * having PG_reserved set). Enforcing this consistency between + * head and tail pages allows drivers to optimize away a check + * on the head page when they need know if put_page() is needed + * after get_user_pages(). + */ + __ClearPageReserved(p); + set_page_count(p, 0); + p->first_page = page; + } } /* - * 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. + * PageHuge() only returns true for hugetlbfs pages, but not for normal or + * transparent huge pages. See the PageTransHuge() documentation for more + * details. */ -static int adjust_pool_surplus(int delta) +int PageHuge(struct page *page) { - static int prev_nid; - int nid = prev_nid; - int ret = 0; + if (!PageCompound(page)) + return 0; - VM_BUG_ON(delta != -1 && delta != 1); - do { - nid = next_node(nid, node_online_map); - if (nid == MAX_NUMNODES) - nid = first_node(node_online_map); + page = compound_head(page); + return get_compound_page_dtor(page) == free_huge_page; +} +EXPORT_SYMBOL_GPL(PageHuge); - /* To shrink on this node, there must be a surplus page */ - if (delta < 0 && !surplus_huge_pages_node[nid]) - continue; - /* Surplus cannot exceed the total number of pages */ - if (delta > 0 && surplus_huge_pages_node[nid] >= - nr_huge_pages_node[nid]) - continue; +/* + * 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; - surplus_huge_pages += delta; - surplus_huge_pages_node[nid] += delta; - ret = 1; - break; - } while (nid != prev_nid); + return get_compound_page_dtor(page_head) == free_huge_page; +} - prev_nid = nid; - return ret; +pgoff_t __basepage_index(struct page *page) +{ + struct page *page_head = compound_head(page); + pgoff_t index = page_index(page_head); + unsigned long compound_idx; + + if (!PageHuge(page_head)) + return page_index(page); + + if (compound_order(page_head) >= MAX_ORDER) + compound_idx = page_to_pfn(page) - page_to_pfn(page_head); + else + compound_idx = page - page_head; + + return (index << compound_order(page_head)) + compound_idx; } -static struct page *alloc_fresh_huge_page_node(int nid) +static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) { struct page *page; - page = alloc_pages_node(nid, - htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|__GFP_NOWARN, - HUGETLB_PAGE_ORDER); + page = alloc_pages_exact_node(nid, + htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| + __GFP_REPEAT|__GFP_NOWARN, + huge_page_order(h)); if (page) { - set_compound_page_dtor(page, free_huge_page); - spin_lock(&hugetlb_lock); - nr_huge_pages++; - nr_huge_pages_node[nid]++; - spin_unlock(&hugetlb_lock); - put_page(page); /* free it into the hugepage allocator */ + if (arch_prepare_hugepage(page)) { + __free_pages(page, huge_page_order(h)); + return NULL; + } + prep_new_huge_page(h, page, nid); } return page; } -static int alloc_fresh_huge_page(void) +static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) { struct page *page; - int start_nid; - int next_nid; + int nr_nodes, node; int ret = 0; - start_nid = hugetlb_next_nid; - - do { - page = alloc_fresh_huge_page_node(hugetlb_next_nid); - if (page) + for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { + page = alloc_fresh_huge_page_node(h, node); + if (page) { ret = 1; + break; + } + } + + if (ret) + count_vm_event(HTLB_BUDDY_PGALLOC); + else + count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); + + return ret; +} + +/* + * Free huge page from pool from next node to free. + * Attempt to keep persistent huge pages more or less + * balanced over allowed nodes. + * Called with hugetlb_lock locked. + */ +static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, + bool acct_surplus) +{ + int nr_nodes, node; + int ret = 0; + + for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { /* - * Use a helper variable to find the next node and then - * copy it back to hugetlb_next_nid afterwards: - * otherwise there's a window in which a racer might - * pass invalid nid MAX_NUMNODES to alloc_pages_node. - * But we don't need to use a spin_lock here: it really - * doesn't matter if occasionally a racer chooses the - * same nid as we do. Move nid forward in the mask even - * if we just successfully allocated a hugepage so that - * the next caller gets hugepages on the next node. + * If we're returning unused surplus pages, only examine + * nodes with surplus pages. */ - next_nid = next_node(hugetlb_next_nid, node_online_map); - if (next_nid == MAX_NUMNODES) - next_nid = first_node(node_online_map); - hugetlb_next_nid = next_nid; - } while (!page && hugetlb_next_nid != start_nid); + if ((!acct_surplus || h->surplus_huge_pages_node[node]) && + !list_empty(&h->hugepage_freelists[node])) { + struct page *page = + list_entry(h->hugepage_freelists[node].next, + struct page, lru); + list_del(&page->lru); + h->free_huge_pages--; + h->free_huge_pages_node[node]--; + if (acct_surplus) { + h->surplus_huge_pages--; + h->surplus_huge_pages_node[node]--; + } + update_and_free_page(h, page); + ret = 1; + break; + } + } return ret; } -static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, - unsigned long address) +/* + * Dissolve a given free hugepage into free buddy pages. This function does + * nothing for in-use (including surplus) hugepages. + */ +static void dissolve_free_huge_page(struct page *page) +{ + spin_lock(&hugetlb_lock); + if (PageHuge(page) && !page_count(page)) { + struct hstate *h = page_hstate(page); + int nid = page_to_nid(page); + list_del(&page->lru); + h->free_huge_pages--; + h->free_huge_pages_node[nid]--; + update_and_free_page(h, page); + } + spin_unlock(&hugetlb_lock); +} + +/* + * Dissolve free hugepages in a given pfn range. Used by memory hotplug to + * make specified memory blocks removable from the system. + * Note that start_pfn should aligned with (minimum) hugepage size. + */ +void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) +{ + unsigned int order = 8 * sizeof(void *); + unsigned long pfn; + struct hstate *h; + + /* Set scan step to minimum hugepage size */ + for_each_hstate(h) + if (order > huge_page_order(h)) + order = huge_page_order(h); + VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order)); + for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) + dissolve_free_huge_page(pfn_to_page(pfn)); +} + +static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) { struct page *page; - unsigned int nid; + unsigned int r_nid; + + if (hstate_is_gigantic(h)) + return NULL; /* * Assume we will successfully allocate the surplus page to @@ -272,36 +1130,45 @@ static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, * per-node value is checked there. */ spin_lock(&hugetlb_lock); - if (surplus_huge_pages >= nr_overcommit_huge_pages) { + if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { spin_unlock(&hugetlb_lock); return NULL; } else { - nr_huge_pages++; - surplus_huge_pages++; + h->nr_huge_pages++; + h->surplus_huge_pages++; } spin_unlock(&hugetlb_lock); - page = alloc_pages(htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN, - HUGETLB_PAGE_ORDER); + if (nid == NUMA_NO_NODE) + page = alloc_pages(htlb_alloc_mask(h)|__GFP_COMP| + __GFP_REPEAT|__GFP_NOWARN, + huge_page_order(h)); + else + page = alloc_pages_exact_node(nid, + htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| + __GFP_REPEAT|__GFP_NOWARN, huge_page_order(h)); + + if (page && arch_prepare_hugepage(page)) { + __free_pages(page, huge_page_order(h)); + page = NULL; + } spin_lock(&hugetlb_lock); if (page) { - /* - * This page is now managed by the hugetlb allocator and has - * no users -- drop the buddy allocator's reference. - */ - put_page_testzero(page); - VM_BUG_ON(page_count(page)); - nid = page_to_nid(page); + INIT_LIST_HEAD(&page->lru); + r_nid = page_to_nid(page); set_compound_page_dtor(page, free_huge_page); + set_hugetlb_cgroup(page, NULL); /* * We incremented the global counters already */ - nr_huge_pages_node[nid]++; - surplus_huge_pages_node[nid]++; + h->nr_huge_pages_node[r_nid]++; + h->surplus_huge_pages_node[r_nid]++; + __count_vm_event(HTLB_BUDDY_PGALLOC); } else { - nr_huge_pages--; - surplus_huge_pages--; + h->nr_huge_pages--; + h->surplus_huge_pages--; + __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); } spin_unlock(&hugetlb_lock); @@ -309,19 +1176,40 @@ static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, } /* - * Increase the hugetlb pool such that it can accomodate a reservation + * This allocation function is useful in the context where vma is irrelevant. + * E.g. soft-offlining uses this function because it only cares physical + * address of error page. + */ +struct page *alloc_huge_page_node(struct hstate *h, int nid) +{ + struct page *page = NULL; + + spin_lock(&hugetlb_lock); + if (h->free_huge_pages - h->resv_huge_pages > 0) + page = dequeue_huge_page_node(h, nid); + spin_unlock(&hugetlb_lock); + + if (!page) + page = alloc_buddy_huge_page(h, nid); + + return page; +} + +/* + * Increase the hugetlb pool such that it can accommodate a reservation * of size 'delta'. */ -static int gather_surplus_pages(int delta) +static int gather_surplus_pages(struct hstate *h, int delta) { struct list_head surplus_list; struct page *page, *tmp; int ret, i; int needed, allocated; + bool alloc_ok = true; - needed = (resv_huge_pages + delta) - free_huge_pages; + needed = (h->resv_huge_pages + delta) - h->free_huge_pages; if (needed <= 0) { - resv_huge_pages += delta; + h->resv_huge_pages += delta; return 0; } @@ -332,60 +1220,63 @@ static int gather_surplus_pages(int delta) retry: spin_unlock(&hugetlb_lock); for (i = 0; i < needed; i++) { - page = alloc_buddy_huge_page(NULL, 0); + page = alloc_buddy_huge_page(h, NUMA_NO_NODE); if (!page) { - /* - * We were not able to allocate enough pages to - * satisfy the entire reservation so we free what - * we've allocated so far. - */ - spin_lock(&hugetlb_lock); - needed = 0; - goto free; + alloc_ok = false; + break; } - list_add(&page->lru, &surplus_list); } - allocated += needed; + allocated += i; /* * After retaking hugetlb_lock, we need to recalculate 'needed' * because either resv_huge_pages or free_huge_pages may have changed. */ spin_lock(&hugetlb_lock); - needed = (resv_huge_pages + delta) - (free_huge_pages + allocated); - if (needed > 0) - goto retry; - + 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 accomodate the reservation. Add the appropriate number + * 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; - resv_huge_pages += delta; + h->resv_huge_pages += delta; ret = 0; -free: + + /* Free the needed pages to the hugetlb pool */ list_for_each_entry_safe(page, tmp, &surplus_list, lru) { - list_del(&page->lru); - if ((--needed) >= 0) - enqueue_huge_page(page); - else { - /* - * The page has a reference count of zero already, so - * call free_huge_page directly instead of using - * put_page. This must be done with hugetlb_lock - * unlocked which is safe because free_huge_page takes - * hugetlb_lock before deciding how to free the page. - */ - spin_unlock(&hugetlb_lock); - free_huge_page(page); - spin_lock(&hugetlb_lock); - } + if ((--needed) < 0) + break; + /* + * This page is now managed by the hugetlb allocator and has + * no users -- drop the buddy allocator's reference. + */ + put_page_testzero(page); + VM_BUG_ON_PAGE(page_count(page), page); + enqueue_huge_page(h, page); } +free: + spin_unlock(&hugetlb_lock); + + /* Free unnecessary surplus pages to the buddy allocator */ + list_for_each_entry_safe(page, tmp, &surplus_list, lru) + put_page(page); + spin_lock(&hugetlb_lock); return ret; } @@ -394,173 +1285,343 @@ free: * When releasing a hugetlb pool reservation, any surplus pages that were * allocated to satisfy the reservation must be explicitly freed if they were * never used. + * Called with hugetlb_lock held. */ -static void return_unused_surplus_pages(unsigned long unused_resv_pages) +static void return_unused_surplus_pages(struct hstate *h, + unsigned long unused_resv_pages) { - static int nid = -1; - struct page *page; unsigned long nr_pages; + /* Uncommit the reservation */ + h->resv_huge_pages -= unused_resv_pages; + + /* Cannot return gigantic pages currently */ + if (hstate_is_gigantic(h)) + return; + + nr_pages = min(unused_resv_pages, h->surplus_huge_pages); + /* * We want to release as many surplus pages as possible, spread - * evenly across all nodes. Iterate across all nodes until we - * can no longer free unreserved surplus pages. This occurs when - * the nodes with surplus pages have no free pages. + * evenly across all nodes with memory. Iterate across these nodes + * until we can no longer free unreserved surplus pages. This occurs + * when the nodes with surplus pages have no free pages. + * free_pool_huge_page() will balance the the freed pages across the + * on-line nodes with memory and will handle the hstate accounting. */ - unsigned long remaining_iterations = num_online_nodes(); - - /* Uncommit the reservation */ - resv_huge_pages -= unused_resv_pages; + while (nr_pages--) { + if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1)) + break; + cond_resched_lock(&hugetlb_lock); + } +} - nr_pages = min(unused_resv_pages, surplus_huge_pages); +/* + * Determine if the huge page at addr within the vma has an associated + * reservation. Where it does not we will need to logically increase + * reservation and actually increase subpool usage before an allocation + * can occur. Where any new reservation would be required the + * reservation change is prepared, but not committed. Once the page + * has been allocated from the subpool and instantiated the change should + * be committed via vma_commit_reservation. No action is required on + * failure. + */ +static long vma_needs_reservation(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr) +{ + struct resv_map *resv; + pgoff_t idx; + long chg; - while (remaining_iterations-- && nr_pages) { - nid = next_node(nid, node_online_map); - if (nid == MAX_NUMNODES) - nid = first_node(node_online_map); + resv = vma_resv_map(vma); + if (!resv) + return 1; - if (!surplus_huge_pages_node[nid]) - continue; + idx = vma_hugecache_offset(h, vma, addr); + chg = region_chg(resv, idx, idx + 1); - if (!list_empty(&hugepage_freelists[nid])) { - page = list_entry(hugepage_freelists[nid].next, - struct page, lru); - list_del(&page->lru); - update_and_free_page(page); - free_huge_pages--; - free_huge_pages_node[nid]--; - surplus_huge_pages--; - surplus_huge_pages_node[nid]--; - nr_pages--; - remaining_iterations = num_online_nodes(); - } - } + if (vma->vm_flags & VM_MAYSHARE) + return chg; + else + return chg < 0 ? chg : 0; } +static void vma_commit_reservation(struct hstate *h, + struct vm_area_struct *vma, unsigned long addr) +{ + struct resv_map *resv; + pgoff_t idx; + resv = vma_resv_map(vma); + if (!resv) + return; -static struct page *alloc_huge_page_shared(struct vm_area_struct *vma, - unsigned long addr) + idx = vma_hugecache_offset(h, vma, addr); + region_add(resv, idx, idx + 1); +} + +static struct page *alloc_huge_page(struct vm_area_struct *vma, + unsigned long addr, int avoid_reserve) { + struct hugepage_subpool *spool = subpool_vma(vma); + struct hstate *h = hstate_vma(vma); struct page *page; + long chg; + int ret, idx; + struct hugetlb_cgroup *h_cg; + + idx = hstate_index(h); + /* + * Processes that did not create the mapping will have no + * reserves and will not have accounted against subpool + * limit. Check that the subpool limit can be made before + * satisfying the allocation MAP_NORESERVE mappings may also + * need pages and subpool limit allocated allocated if no reserve + * mapping overlaps. + */ + chg = vma_needs_reservation(h, vma, addr); + if (chg < 0) + return ERR_PTR(-ENOMEM); + if (chg || avoid_reserve) + if (hugepage_subpool_get_pages(spool, 1)) + return ERR_PTR(-ENOSPC); + + ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); + if (ret) + goto out_subpool_put; spin_lock(&hugetlb_lock); - page = dequeue_huge_page_vma(vma, addr); + page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg); + if (!page) { + spin_unlock(&hugetlb_lock); + page = alloc_buddy_huge_page(h, NUMA_NO_NODE); + if (!page) + goto out_uncharge_cgroup; + + spin_lock(&hugetlb_lock); + list_move(&page->lru, &h->hugepage_activelist); + /* Fall through */ + } + hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); spin_unlock(&hugetlb_lock); - return page ? page : ERR_PTR(-VM_FAULT_OOM); + + set_page_private(page, (unsigned long)spool); + + vma_commit_reservation(h, vma, addr); + return page; + +out_uncharge_cgroup: + hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); +out_subpool_put: + if (chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); + return ERR_PTR(-ENOSPC); } -static struct page *alloc_huge_page_private(struct vm_area_struct *vma, - unsigned long addr) +/* + * alloc_huge_page()'s wrapper which simply returns the page if allocation + * succeeds, otherwise NULL. This function is called from new_vma_page(), + * where no ERR_VALUE is expected to be returned. + */ +struct page *alloc_huge_page_noerr(struct vm_area_struct *vma, + unsigned long addr, int avoid_reserve) { - struct page *page = NULL; + struct page *page = alloc_huge_page(vma, addr, avoid_reserve); + if (IS_ERR(page)) + page = NULL; + return page; +} - if (hugetlb_get_quota(vma->vm_file->f_mapping, 1)) - return ERR_PTR(-VM_FAULT_SIGBUS); +int __weak alloc_bootmem_huge_page(struct hstate *h) +{ + struct huge_bootmem_page *m; + int nr_nodes, node; - spin_lock(&hugetlb_lock); - if (free_huge_pages > resv_huge_pages) - page = dequeue_huge_page_vma(vma, addr); - spin_unlock(&hugetlb_lock); - if (!page) { - page = alloc_buddy_huge_page(vma, addr); - if (!page) { - hugetlb_put_quota(vma->vm_file->f_mapping, 1); - return ERR_PTR(-VM_FAULT_OOM); + for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { + void *addr; + + addr = memblock_virt_alloc_try_nid_nopanic( + huge_page_size(h), huge_page_size(h), + 0, BOOTMEM_ALLOC_ACCESSIBLE, node); + if (addr) { + /* + * Use the beginning of the huge page to store the + * huge_bootmem_page struct (until gather_bootmem + * puts them into the mem_map). + */ + m = addr; + goto found; } } - return page; + return 0; + +found: + BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); + /* Put them into a private list first because mem_map is not up yet */ + list_add(&m->list, &huge_boot_pages); + m->hstate = h; + return 1; } -static struct page *alloc_huge_page(struct vm_area_struct *vma, - unsigned long addr) +static void __init prep_compound_huge_page(struct page *page, int order) { - struct page *page; - struct address_space *mapping = vma->vm_file->f_mapping; - - if (vma->vm_flags & VM_MAYSHARE) - page = alloc_huge_page_shared(vma, addr); + if (unlikely(order > (MAX_ORDER - 1))) + prep_compound_gigantic_page(page, order); else - page = alloc_huge_page_private(vma, addr); - - if (!IS_ERR(page)) { - set_page_refcounted(page); - set_page_private(page, (unsigned long) mapping); - } - return page; + prep_compound_page(page, order); } -static int __init hugetlb_init(void) +/* Put bootmem huge pages into the standard lists after mem_map is up */ +static void __init gather_bootmem_prealloc(void) { - unsigned long i; + struct huge_bootmem_page *m; - if (HPAGE_SHIFT == 0) - return 0; + list_for_each_entry(m, &huge_boot_pages, list) { + struct hstate *h = m->hstate; + struct page *page; - for (i = 0; i < MAX_NUMNODES; ++i) - INIT_LIST_HEAD(&hugepage_freelists[i]); +#ifdef CONFIG_HIGHMEM + page = pfn_to_page(m->phys >> PAGE_SHIFT); + memblock_free_late(__pa(m), + sizeof(struct huge_bootmem_page)); +#else + page = virt_to_page(m); +#endif + WARN_ON(page_count(page) != 1); + prep_compound_huge_page(page, h->order); + WARN_ON(PageReserved(page)); + prep_new_huge_page(h, page, page_to_nid(page)); + /* + * If we had gigantic hugepages allocated at boot time, we need + * to restore the 'stolen' pages to totalram_pages in order to + * fix confusing memory reports from free(1) and another + * side-effects, like CommitLimit going negative. + */ + if (hstate_is_gigantic(h)) + adjust_managed_page_count(page, 1 << h->order); + } +} - hugetlb_next_nid = first_node(node_online_map); +static void __init hugetlb_hstate_alloc_pages(struct hstate *h) +{ + unsigned long i; - for (i = 0; i < max_huge_pages; ++i) { - if (!alloc_fresh_huge_page()) + for (i = 0; i < h->max_huge_pages; ++i) { + if (hstate_is_gigantic(h)) { + if (!alloc_bootmem_huge_page(h)) + break; + } else if (!alloc_fresh_huge_page(h, + &node_states[N_MEMORY])) break; } - max_huge_pages = free_huge_pages = nr_huge_pages = i; - printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); - return 0; + h->max_huge_pages = i; } -module_init(hugetlb_init); -static int __init hugetlb_setup(char *s) +static void __init hugetlb_init_hstates(void) { - if (sscanf(s, "%lu", &max_huge_pages) <= 0) - max_huge_pages = 0; - return 1; + struct hstate *h; + + for_each_hstate(h) { + /* oversize hugepages were init'ed in early boot */ + if (!hstate_is_gigantic(h)) + hugetlb_hstate_alloc_pages(h); + } } -__setup("hugepages=", hugetlb_setup); -static unsigned int cpuset_mems_nr(unsigned int *array) +static char * __init memfmt(char *buf, unsigned long n) { - int node; - unsigned int nr = 0; + if (n >= (1UL << 30)) + sprintf(buf, "%lu GB", n >> 30); + else if (n >= (1UL << 20)) + sprintf(buf, "%lu MB", n >> 20); + else + sprintf(buf, "%lu KB", n >> 10); + return buf; +} - for_each_node_mask(node, cpuset_current_mems_allowed) - nr += array[node]; +static void __init report_hugepages(void) +{ + struct hstate *h; - return nr; + for_each_hstate(h) { + char buf[32]; + pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n", + memfmt(buf, huge_page_size(h)), + h->free_huge_pages); + } } -#ifdef CONFIG_SYSCTL #ifdef CONFIG_HIGHMEM -static void try_to_free_low(unsigned long count) +static void try_to_free_low(struct hstate *h, unsigned long count, + nodemask_t *nodes_allowed) { int i; - for (i = 0; i < MAX_NUMNODES; ++i) { + if (hstate_is_gigantic(h)) + return; + + for_each_node_mask(i, *nodes_allowed) { struct page *page, *next; - list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { - if (count >= nr_huge_pages) + struct list_head *freel = &h->hugepage_freelists[i]; + list_for_each_entry_safe(page, next, freel, lru) { + if (count >= h->nr_huge_pages) return; if (PageHighMem(page)) continue; list_del(&page->lru); - update_and_free_page(page); - free_huge_pages--; - free_huge_pages_node[page_to_nid(page)]--; + update_and_free_page(h, page); + h->free_huge_pages--; + h->free_huge_pages_node[page_to_nid(page)]--; } } } #else -static inline void try_to_free_low(unsigned long count) +static inline void try_to_free_low(struct hstate *h, unsigned long count, + nodemask_t *nodes_allowed) { } #endif -#define persistent_huge_pages (nr_huge_pages - surplus_huge_pages) -static unsigned long set_max_huge_pages(unsigned long count) +/* + * Increment or decrement surplus_huge_pages. Keep node-specific counters + * balanced by operating on them in a round-robin fashion. + * Returns 1 if an adjustment was made. + */ +static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, + int delta) +{ + int nr_nodes, node; + + VM_BUG_ON(delta != -1 && delta != 1); + + if (delta < 0) { + for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { + if (h->surplus_huge_pages_node[node]) + goto found; + } + } else { + for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { + if (h->surplus_huge_pages_node[node] < + h->nr_huge_pages_node[node]) + goto found; + } + } + return 0; + +found: + h->surplus_huge_pages += delta; + h->surplus_huge_pages_node[node] += delta; + return 1; +} + +#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) +static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, + nodemask_t *nodes_allowed) { unsigned long min_count, ret; + if (hstate_is_gigantic(h) && !gigantic_page_supported()) + return h->max_huge_pages; + /* * Increase the pool size * First take pages out of surplus state. Then make up the @@ -573,24 +1634,29 @@ static unsigned long set_max_huge_pages(unsigned long count) * within all the constraints specified by the sysctls. */ spin_lock(&hugetlb_lock); - while (surplus_huge_pages && count > persistent_huge_pages) { - if (!adjust_pool_surplus(-1)) + while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { + if (!adjust_pool_surplus(h, nodes_allowed, -1)) break; } - while (count > persistent_huge_pages) { - int ret; + while (count > persistent_huge_pages(h)) { /* * If this allocation races such that we no longer need the * page, free_huge_page will handle it by freeing the page * and reducing the surplus. */ spin_unlock(&hugetlb_lock); - ret = alloc_fresh_huge_page(); + if (hstate_is_gigantic(h)) + ret = alloc_fresh_gigantic_page(h, nodes_allowed); + else + ret = alloc_fresh_huge_page(h, nodes_allowed); spin_lock(&hugetlb_lock); if (!ret) goto out; + /* Bail for signals. Probably ctrl-c from user */ + if (signal_pending(current)) + goto out; } /* @@ -608,89 +1674,803 @@ static unsigned long set_max_huge_pages(unsigned long count) * and won't grow the pool anywhere else. Not until one of the * sysctls are changed, or the surplus pages go out of use. */ - min_count = resv_huge_pages + nr_huge_pages - free_huge_pages; + min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; min_count = max(count, min_count); - try_to_free_low(min_count); - while (min_count < persistent_huge_pages) { - struct page *page = dequeue_huge_page(); - if (!page) + try_to_free_low(h, min_count, nodes_allowed); + while (min_count < persistent_huge_pages(h)) { + if (!free_pool_huge_page(h, nodes_allowed, 0)) break; - update_and_free_page(page); + cond_resched_lock(&hugetlb_lock); } - while (count < persistent_huge_pages) { - if (!adjust_pool_surplus(1)) + while (count < persistent_huge_pages(h)) { + if (!adjust_pool_surplus(h, nodes_allowed, 1)) break; } out: - ret = persistent_huge_pages; + ret = persistent_huge_pages(h); spin_unlock(&hugetlb_lock); return ret; } -int hugetlb_sysctl_handler(struct ctl_table *table, int write, - struct file *file, void __user *buffer, - size_t *length, loff_t *ppos) +#define HSTATE_ATTR_RO(_name) \ + static struct kobj_attribute _name##_attr = __ATTR_RO(_name) + +#define HSTATE_ATTR(_name) \ + static struct kobj_attribute _name##_attr = \ + __ATTR(_name, 0644, _name##_show, _name##_store) + +static struct kobject *hugepages_kobj; +static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; + +static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); + +static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) { - proc_doulongvec_minmax(table, write, file, buffer, length, ppos); - max_huge_pages = set_max_huge_pages(max_huge_pages); - return 0; + int i; + + for (i = 0; i < HUGE_MAX_HSTATE; i++) + if (hstate_kobjs[i] == kobj) { + if (nidp) + *nidp = NUMA_NO_NODE; + return &hstates[i]; + } + + return kobj_to_node_hstate(kobj, nidp); } -int hugetlb_treat_movable_handler(struct ctl_table *table, int write, - struct file *file, void __user *buffer, - size_t *length, loff_t *ppos) +static ssize_t nr_hugepages_show_common(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) { - proc_dointvec(table, write, file, buffer, length, ppos); - if (hugepages_treat_as_movable) - htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; + struct hstate *h; + unsigned long nr_huge_pages; + int nid; + + h = kobj_to_hstate(kobj, &nid); + if (nid == NUMA_NO_NODE) + nr_huge_pages = h->nr_huge_pages; else - htlb_alloc_mask = GFP_HIGHUSER; - return 0; + nr_huge_pages = h->nr_huge_pages_node[nid]; + + return sprintf(buf, "%lu\n", nr_huge_pages); } -int hugetlb_overcommit_handler(struct ctl_table *table, int write, - struct file *file, void __user *buffer, - size_t *length, loff_t *ppos) +static ssize_t nr_hugepages_store_common(bool obey_mempolicy, + struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t len) { - proc_doulongvec_minmax(table, write, file, buffer, length, ppos); + int err; + int nid; + unsigned long count; + struct hstate *h; + NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); + + err = kstrtoul(buf, 10, &count); + if (err) + goto out; + + h = kobj_to_hstate(kobj, &nid); + if (hstate_is_gigantic(h) && !gigantic_page_supported()) { + err = -EINVAL; + goto out; + } + + if (nid == NUMA_NO_NODE) { + /* + * global hstate attribute + */ + if (!(obey_mempolicy && + init_nodemask_of_mempolicy(nodes_allowed))) { + NODEMASK_FREE(nodes_allowed); + nodes_allowed = &node_states[N_MEMORY]; + } + } else if (nodes_allowed) { + /* + * per node hstate attribute: adjust count to global, + * but restrict alloc/free to the specified node. + */ + count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; + init_nodemask_of_node(nodes_allowed, nid); + } else + nodes_allowed = &node_states[N_MEMORY]; + + h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed); + + if (nodes_allowed != &node_states[N_MEMORY]) + NODEMASK_FREE(nodes_allowed); + + return len; +out: + NODEMASK_FREE(nodes_allowed); + return err; +} + +static ssize_t nr_hugepages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return nr_hugepages_show_common(kobj, attr, buf); +} + +static ssize_t nr_hugepages_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t len) +{ + return nr_hugepages_store_common(false, kobj, attr, buf, len); +} +HSTATE_ATTR(nr_hugepages); + +#ifdef CONFIG_NUMA + +/* + * hstate attribute for optionally mempolicy-based constraint on persistent + * huge page alloc/free. + */ +static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return nr_hugepages_show_common(kobj, attr, buf); +} + +static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t len) +{ + return nr_hugepages_store_common(true, kobj, attr, buf, len); +} +HSTATE_ATTR(nr_hugepages_mempolicy); +#endif + + +static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct hstate *h = kobj_to_hstate(kobj, NULL); + return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages); +} + +static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, + struct kobj_attribute *attr, const char *buf, size_t count) +{ + int err; + unsigned long input; + struct hstate *h = kobj_to_hstate(kobj, NULL); + + if (hstate_is_gigantic(h)) + return -EINVAL; + + err = kstrtoul(buf, 10, &input); + if (err) + return err; + spin_lock(&hugetlb_lock); - nr_overcommit_huge_pages = sysctl_overcommit_huge_pages; + h->nr_overcommit_huge_pages = input; spin_unlock(&hugetlb_lock); + + return count; +} +HSTATE_ATTR(nr_overcommit_hugepages); + +static ssize_t free_hugepages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct hstate *h; + unsigned long free_huge_pages; + int nid; + + h = kobj_to_hstate(kobj, &nid); + if (nid == NUMA_NO_NODE) + free_huge_pages = h->free_huge_pages; + else + free_huge_pages = h->free_huge_pages_node[nid]; + + return sprintf(buf, "%lu\n", free_huge_pages); +} +HSTATE_ATTR_RO(free_hugepages); + +static ssize_t resv_hugepages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct hstate *h = kobj_to_hstate(kobj, NULL); + return sprintf(buf, "%lu\n", h->resv_huge_pages); +} +HSTATE_ATTR_RO(resv_hugepages); + +static ssize_t surplus_hugepages_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + struct hstate *h; + unsigned long surplus_huge_pages; + int nid; + + h = kobj_to_hstate(kobj, &nid); + if (nid == NUMA_NO_NODE) + surplus_huge_pages = h->surplus_huge_pages; + else + surplus_huge_pages = h->surplus_huge_pages_node[nid]; + + return sprintf(buf, "%lu\n", surplus_huge_pages); +} +HSTATE_ATTR_RO(surplus_hugepages); + +static struct attribute *hstate_attrs[] = { + &nr_hugepages_attr.attr, + &nr_overcommit_hugepages_attr.attr, + &free_hugepages_attr.attr, + &resv_hugepages_attr.attr, + &surplus_hugepages_attr.attr, +#ifdef CONFIG_NUMA + &nr_hugepages_mempolicy_attr.attr, +#endif + NULL, +}; + +static struct attribute_group hstate_attr_group = { + .attrs = hstate_attrs, +}; + +static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, + struct kobject **hstate_kobjs, + struct attribute_group *hstate_attr_group) +{ + int retval; + int hi = hstate_index(h); + + hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); + if (!hstate_kobjs[hi]) + return -ENOMEM; + + retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); + if (retval) + kobject_put(hstate_kobjs[hi]); + + return retval; +} + +static void __init hugetlb_sysfs_init(void) +{ + struct hstate *h; + int err; + + hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); + if (!hugepages_kobj) + return; + + for_each_hstate(h) { + err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, + hstate_kobjs, &hstate_attr_group); + if (err) + pr_err("Hugetlb: Unable to add hstate %s", h->name); + } +} + +#ifdef CONFIG_NUMA + +/* + * node_hstate/s - associate per node hstate attributes, via their kobjects, + * with node devices in node_devices[] using a parallel array. The array + * index of a node device or _hstate == node id. + * This is here to avoid any static dependency of the node device driver, in + * the base kernel, on the hugetlb module. + */ +struct node_hstate { + struct kobject *hugepages_kobj; + struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; +}; +struct node_hstate node_hstates[MAX_NUMNODES]; + +/* + * A subset of global hstate attributes for node devices + */ +static struct attribute *per_node_hstate_attrs[] = { + &nr_hugepages_attr.attr, + &free_hugepages_attr.attr, + &surplus_hugepages_attr.attr, + NULL, +}; + +static struct attribute_group per_node_hstate_attr_group = { + .attrs = per_node_hstate_attrs, +}; + +/* + * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. + * Returns node id via non-NULL nidp. + */ +static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) +{ + int nid; + + for (nid = 0; nid < nr_node_ids; nid++) { + struct node_hstate *nhs = &node_hstates[nid]; + int i; + for (i = 0; i < HUGE_MAX_HSTATE; i++) + if (nhs->hstate_kobjs[i] == kobj) { + if (nidp) + *nidp = nid; + return &hstates[i]; + } + } + + BUG(); + return NULL; +} + +/* + * Unregister hstate attributes from a single node device. + * No-op if no hstate attributes attached. + */ +static void hugetlb_unregister_node(struct node *node) +{ + struct hstate *h; + struct node_hstate *nhs = &node_hstates[node->dev.id]; + + if (!nhs->hugepages_kobj) + return; /* no hstate attributes */ + + for_each_hstate(h) { + int idx = hstate_index(h); + if (nhs->hstate_kobjs[idx]) { + kobject_put(nhs->hstate_kobjs[idx]); + nhs->hstate_kobjs[idx] = NULL; + } + } + + kobject_put(nhs->hugepages_kobj); + nhs->hugepages_kobj = NULL; +} + +/* + * hugetlb module exit: unregister hstate attributes from node devices + * that have them. + */ +static void hugetlb_unregister_all_nodes(void) +{ + int nid; + + /* + * disable node device registrations. + */ + register_hugetlbfs_with_node(NULL, NULL); + + /* + * remove hstate attributes from any nodes that have them. + */ + for (nid = 0; nid < nr_node_ids; nid++) + hugetlb_unregister_node(node_devices[nid]); +} + +/* + * Register hstate attributes for a single node device. + * No-op if attributes already registered. + */ +static void hugetlb_register_node(struct node *node) +{ + struct hstate *h; + struct node_hstate *nhs = &node_hstates[node->dev.id]; + int err; + + if (nhs->hugepages_kobj) + return; /* already allocated */ + + nhs->hugepages_kobj = kobject_create_and_add("hugepages", + &node->dev.kobj); + if (!nhs->hugepages_kobj) + return; + + for_each_hstate(h) { + err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, + nhs->hstate_kobjs, + &per_node_hstate_attr_group); + if (err) { + pr_err("Hugetlb: Unable to add hstate %s for node %d\n", + h->name, node->dev.id); + hugetlb_unregister_node(node); + break; + } + } +} + +/* + * hugetlb init time: register hstate attributes for all registered node + * devices of nodes that have memory. All on-line nodes should have + * registered their associated device by this time. + */ +static void hugetlb_register_all_nodes(void) +{ + int nid; + + for_each_node_state(nid, N_MEMORY) { + struct node *node = node_devices[nid]; + if (node->dev.id == nid) + hugetlb_register_node(node); + } + + /* + * Let the node device driver know we're here so it can + * [un]register hstate attributes on node hotplug. + */ + register_hugetlbfs_with_node(hugetlb_register_node, + hugetlb_unregister_node); +} +#else /* !CONFIG_NUMA */ + +static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) +{ + BUG(); + if (nidp) + *nidp = -1; + return NULL; +} + +static void hugetlb_unregister_all_nodes(void) { } + +static void hugetlb_register_all_nodes(void) { } + +#endif + +static void __exit hugetlb_exit(void) +{ + struct hstate *h; + + hugetlb_unregister_all_nodes(); + + for_each_hstate(h) { + kobject_put(hstate_kobjs[hstate_index(h)]); + } + + kobject_put(hugepages_kobj); + kfree(htlb_fault_mutex_table); +} +module_exit(hugetlb_exit); + +static int __init hugetlb_init(void) +{ + int i; + + if (!hugepages_supported()) + return 0; + + if (!size_to_hstate(default_hstate_size)) { + default_hstate_size = HPAGE_SIZE; + if (!size_to_hstate(default_hstate_size)) + hugetlb_add_hstate(HUGETLB_PAGE_ORDER); + } + default_hstate_idx = hstate_index(size_to_hstate(default_hstate_size)); + if (default_hstate_max_huge_pages) + default_hstate.max_huge_pages = default_hstate_max_huge_pages; + + hugetlb_init_hstates(); + gather_bootmem_prealloc(); + report_hugepages(); + + hugetlb_sysfs_init(); + hugetlb_register_all_nodes(); + hugetlb_cgroup_file_init(); + +#ifdef CONFIG_SMP + num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus()); +#else + num_fault_mutexes = 1; +#endif + htlb_fault_mutex_table = + kmalloc(sizeof(struct mutex) * num_fault_mutexes, GFP_KERNEL); + BUG_ON(!htlb_fault_mutex_table); + + for (i = 0; i < num_fault_mutexes; i++) + mutex_init(&htlb_fault_mutex_table[i]); return 0; } +module_init(hugetlb_init); + +/* Should be called on processing a hugepagesz=... option */ +void __init hugetlb_add_hstate(unsigned order) +{ + struct hstate *h; + unsigned long i; + + if (size_to_hstate(PAGE_SIZE << order)) { + pr_warning("hugepagesz= specified twice, ignoring\n"); + return; + } + BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); + BUG_ON(order == 0); + h = &hstates[hugetlb_max_hstate++]; + h->order = order; + h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); + h->nr_huge_pages = 0; + h->free_huge_pages = 0; + for (i = 0; i < MAX_NUMNODES; ++i) + INIT_LIST_HEAD(&h->hugepage_freelists[i]); + INIT_LIST_HEAD(&h->hugepage_activelist); + h->next_nid_to_alloc = first_node(node_states[N_MEMORY]); + h->next_nid_to_free = first_node(node_states[N_MEMORY]); + snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", + huge_page_size(h)/1024); + + parsed_hstate = h; +} + +static int __init hugetlb_nrpages_setup(char *s) +{ + unsigned long *mhp; + static unsigned long *last_mhp; + + /* + * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter yet, + * so this hugepages= parameter goes to the "default hstate". + */ + if (!hugetlb_max_hstate) + mhp = &default_hstate_max_huge_pages; + else + mhp = &parsed_hstate->max_huge_pages; + + if (mhp == last_mhp) { + pr_warning("hugepages= specified twice without " + "interleaving hugepagesz=, ignoring\n"); + return 1; + } + + if (sscanf(s, "%lu", mhp) <= 0) + *mhp = 0; + + /* + * Global state is always initialized later in hugetlb_init. + * But we need to allocate >= MAX_ORDER hstates here early to still + * use the bootmem allocator. + */ + if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER) + hugetlb_hstate_alloc_pages(parsed_hstate); + + last_mhp = mhp; + + return 1; +} +__setup("hugepages=", hugetlb_nrpages_setup); + +static int __init hugetlb_default_setup(char *s) +{ + default_hstate_size = memparse(s, &s); + return 1; +} +__setup("default_hugepagesz=", hugetlb_default_setup); + +static unsigned int cpuset_mems_nr(unsigned int *array) +{ + int node; + unsigned int nr = 0; + + for_each_node_mask(node, cpuset_current_mems_allowed) + nr += array[node]; + + return nr; +} + +#ifdef CONFIG_SYSCTL +static int hugetlb_sysctl_handler_common(bool obey_mempolicy, + struct ctl_table *table, int write, + void __user *buffer, size_t *length, loff_t *ppos) +{ + struct hstate *h = &default_hstate; + unsigned long tmp; + int ret; + + if (!hugepages_supported()) + return -ENOTSUPP; + + tmp = h->max_huge_pages; + + if (write && hstate_is_gigantic(h) && !gigantic_page_supported()) + return -EINVAL; + + table->data = &tmp; + table->maxlen = sizeof(unsigned long); + ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); + if (ret) + goto out; + + if (write) { + NODEMASK_ALLOC(nodemask_t, nodes_allowed, + GFP_KERNEL | __GFP_NORETRY); + if (!(obey_mempolicy && + init_nodemask_of_mempolicy(nodes_allowed))) { + NODEMASK_FREE(nodes_allowed); + nodes_allowed = &node_states[N_MEMORY]; + } + h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); + + if (nodes_allowed != &node_states[N_MEMORY]) + NODEMASK_FREE(nodes_allowed); + } +out: + return ret; +} + +int hugetlb_sysctl_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *length, loff_t *ppos) +{ + + return hugetlb_sysctl_handler_common(false, table, write, + buffer, length, ppos); +} + +#ifdef CONFIG_NUMA +int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *length, loff_t *ppos) +{ + return hugetlb_sysctl_handler_common(true, table, write, + buffer, length, ppos); +} +#endif /* CONFIG_NUMA */ + +int hugetlb_overcommit_handler(struct ctl_table *table, int write, + void __user *buffer, + size_t *length, loff_t *ppos) +{ + struct hstate *h = &default_hstate; + unsigned long tmp; + int ret; + + if (!hugepages_supported()) + return -ENOTSUPP; + + tmp = h->nr_overcommit_huge_pages; + + if (write && hstate_is_gigantic(h)) + return -EINVAL; + + table->data = &tmp; + table->maxlen = sizeof(unsigned long); + ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); + if (ret) + goto out; + + if (write) { + spin_lock(&hugetlb_lock); + h->nr_overcommit_huge_pages = tmp; + spin_unlock(&hugetlb_lock); + } +out: + return ret; +} #endif /* CONFIG_SYSCTL */ -int hugetlb_report_meminfo(char *buf) +void hugetlb_report_meminfo(struct seq_file *m) { - return sprintf(buf, - "HugePages_Total: %5lu\n" - "HugePages_Free: %5lu\n" - "HugePages_Rsvd: %5lu\n" - "HugePages_Surp: %5lu\n" - "Hugepagesize: %5lu kB\n", - nr_huge_pages, - free_huge_pages, - resv_huge_pages, - surplus_huge_pages, - HPAGE_SIZE/1024); + struct hstate *h = &default_hstate; + if (!hugepages_supported()) + return; + seq_printf(m, + "HugePages_Total: %5lu\n" + "HugePages_Free: %5lu\n" + "HugePages_Rsvd: %5lu\n" + "HugePages_Surp: %5lu\n" + "Hugepagesize: %8lu kB\n", + h->nr_huge_pages, + h->free_huge_pages, + h->resv_huge_pages, + h->surplus_huge_pages, + 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); } int hugetlb_report_node_meminfo(int nid, char *buf) { + struct hstate *h = &default_hstate; + if (!hugepages_supported()) + return 0; return sprintf(buf, "Node %d HugePages_Total: %5u\n" "Node %d HugePages_Free: %5u\n" "Node %d HugePages_Surp: %5u\n", - nid, nr_huge_pages_node[nid], - nid, free_huge_pages_node[nid], - nid, surplus_huge_pages_node[nid]); + nid, h->nr_huge_pages_node[nid], + nid, h->free_huge_pages_node[nid], + nid, h->surplus_huge_pages_node[nid]); +} + +void hugetlb_show_meminfo(void) +{ + struct hstate *h; + int nid; + + if (!hugepages_supported()) + return; + + for_each_node_state(nid, N_MEMORY) + for_each_hstate(h) + pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n", + nid, + h->nr_huge_pages_node[nid], + h->free_huge_pages_node[nid], + h->surplus_huge_pages_node[nid], + 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); } /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ unsigned long hugetlb_total_pages(void) { - return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE); + struct hstate *h; + unsigned long nr_total_pages = 0; + + for_each_hstate(h) + nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); + return nr_total_pages; +} + +static int hugetlb_acct_memory(struct hstate *h, long delta) +{ + int ret = -ENOMEM; + + spin_lock(&hugetlb_lock); + /* + * When cpuset is configured, it breaks the strict hugetlb page + * reservation as the accounting is done on a global variable. Such + * reservation is completely rubbish in the presence of cpuset because + * the reservation is not checked against page availability for the + * current cpuset. Application can still potentially OOM'ed by kernel + * with lack of free htlb page in cpuset that the task is in. + * Attempt to enforce strict accounting with cpuset is almost + * impossible (or too ugly) because cpuset is too fluid that + * task or memory node can be dynamically moved between cpusets. + * + * The change of semantics for shared hugetlb mapping with cpuset is + * undesirable. However, in order to preserve some of the semantics, + * we fall back to check against current free page availability as + * a best attempt and hopefully to minimize the impact of changing + * semantics that cpuset has. + */ + if (delta > 0) { + if (gather_surplus_pages(h, delta) < 0) + goto out; + + if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { + return_unused_surplus_pages(h, delta); + goto out; + } + } + + ret = 0; + if (delta < 0) + return_unused_surplus_pages(h, (unsigned long) -delta); + +out: + spin_unlock(&hugetlb_lock); + return ret; +} + +static void hugetlb_vm_op_open(struct vm_area_struct *vma) +{ + struct resv_map *resv = vma_resv_map(vma); + + /* + * This new VMA should share its siblings reservation map if present. + * The VMA will only ever have a valid reservation map pointer where + * it is being copied for another still existing VMA. As that VMA + * has a reference to the reservation map it cannot disappear until + * after this open call completes. It is therefore safe to take a + * new reference here without additional locking. + */ + if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) + kref_get(&resv->refs); +} + +static void hugetlb_vm_op_close(struct vm_area_struct *vma) +{ + struct hstate *h = hstate_vma(vma); + struct resv_map *resv = vma_resv_map(vma); + struct hugepage_subpool *spool = subpool_vma(vma); + unsigned long reserve, start, end; + + if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) + return; + + start = vma_hugecache_offset(h, vma, vma->vm_start); + end = vma_hugecache_offset(h, vma, vma->vm_end); + + reserve = (end - start) - region_count(resv, start, end); + + kref_put(&resv->refs, resv_map_release); + + if (reserve) { + hugetlb_acct_memory(h, -reserve); + hugepage_subpool_put_pages(spool, reserve); + } } /* @@ -705,8 +2485,10 @@ static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) return 0; } -struct vm_operations_struct hugetlb_vm_ops = { +const struct vm_operations_struct hugetlb_vm_ops = { .fault = hugetlb_vm_op_fault, + .open = hugetlb_vm_op_open, + .close = hugetlb_vm_op_close, }; static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, @@ -715,13 +2497,15 @@ static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, pte_t entry; if (writable) { - entry = - pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); + entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page, + vma->vm_page_prot))); } else { - entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot)); + entry = huge_pte_wrprotect(mk_huge_pte(page, + vma->vm_page_prot)); } entry = pte_mkyoung(entry); entry = pte_mkhuge(entry); + entry = arch_make_huge_pte(entry, vma, page, writable); return entry; } @@ -731,12 +2515,36 @@ static void set_huge_ptep_writable(struct vm_area_struct *vma, { pte_t entry; - entry = pte_mkwrite(pte_mkdirty(*ptep)); - if (ptep_set_access_flags(vma, address, ptep, entry, 1)) { - update_mmu_cache(vma, address, entry); - } + entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep))); + if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) + update_mmu_cache(vma, address, ptep); } +static int is_hugetlb_entry_migration(pte_t pte) +{ + swp_entry_t swp; + + if (huge_pte_none(pte) || pte_present(pte)) + return 0; + swp = pte_to_swp_entry(pte); + if (non_swap_entry(swp) && is_migration_entry(swp)) + return 1; + else + return 0; +} + +static int is_hugetlb_entry_hwpoisoned(pte_t pte) +{ + swp_entry_t swp; + + if (huge_pte_none(pte) || pte_present(pte)) + return 0; + swp = pte_to_swp_entry(pte); + if (non_swap_entry(swp) && is_hwpoison_entry(swp)) + return 1; + else + return 0; +} int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma) @@ -745,159 +2553,436 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, struct page *ptepage; unsigned long addr; int cow; + struct hstate *h = hstate_vma(vma); + unsigned long sz = huge_page_size(h); + unsigned long mmun_start; /* For mmu_notifiers */ + unsigned long mmun_end; /* For mmu_notifiers */ + int ret = 0; cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; - for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { + mmun_start = vma->vm_start; + mmun_end = vma->vm_end; + if (cow) + mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end); + + for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { + spinlock_t *src_ptl, *dst_ptl; src_pte = huge_pte_offset(src, addr); if (!src_pte) continue; - dst_pte = huge_pte_alloc(dst, addr); - if (!dst_pte) - goto nomem; + dst_pte = huge_pte_alloc(dst, addr, sz); + if (!dst_pte) { + ret = -ENOMEM; + break; + } /* If the pagetables are shared don't copy or take references */ if (dst_pte == src_pte) continue; - spin_lock(&dst->page_table_lock); - spin_lock(&src->page_table_lock); - if (!pte_none(*src_pte)) { + dst_ptl = huge_pte_lock(h, dst, dst_pte); + src_ptl = huge_pte_lockptr(h, src, src_pte); + spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); + entry = huge_ptep_get(src_pte); + if (huge_pte_none(entry)) { /* skip none entry */ + ; + } else if (unlikely(is_hugetlb_entry_migration(entry) || + is_hugetlb_entry_hwpoisoned(entry))) { + swp_entry_t swp_entry = pte_to_swp_entry(entry); + + if (is_write_migration_entry(swp_entry) && cow) { + /* + * COW mappings require pages in both + * parent and child to be set to read. + */ + make_migration_entry_read(&swp_entry); + entry = swp_entry_to_pte(swp_entry); + set_huge_pte_at(src, addr, src_pte, entry); + } + set_huge_pte_at(dst, addr, dst_pte, entry); + } else { if (cow) - ptep_set_wrprotect(src, addr, src_pte); - entry = *src_pte; + huge_ptep_set_wrprotect(src, addr, src_pte); + entry = huge_ptep_get(src_pte); ptepage = pte_page(entry); get_page(ptepage); + page_dup_rmap(ptepage); set_huge_pte_at(dst, addr, dst_pte, entry); } - spin_unlock(&src->page_table_lock); - spin_unlock(&dst->page_table_lock); + spin_unlock(src_ptl); + spin_unlock(dst_ptl); } - return 0; -nomem: - return -ENOMEM; + if (cow) + mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end); + + return ret; } -void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, - unsigned long end) +void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, + unsigned long start, unsigned long end, + struct page *ref_page) { + int force_flush = 0; struct mm_struct *mm = vma->vm_mm; unsigned long address; pte_t *ptep; pte_t pte; + spinlock_t *ptl; struct page *page; - struct page *tmp; - /* - * A page gathering list, protected by per file i_mmap_lock. The - * lock is used to avoid list corruption from multiple unmapping - * of the same page since we are using page->lru. - */ - LIST_HEAD(page_list); + struct hstate *h = hstate_vma(vma); + unsigned long sz = huge_page_size(h); + const unsigned long mmun_start = start; /* For mmu_notifiers */ + const unsigned long mmun_end = end; /* For mmu_notifiers */ WARN_ON(!is_vm_hugetlb_page(vma)); - BUG_ON(start & ~HPAGE_MASK); - BUG_ON(end & ~HPAGE_MASK); + BUG_ON(start & ~huge_page_mask(h)); + BUG_ON(end & ~huge_page_mask(h)); - spin_lock(&mm->page_table_lock); - for (address = start; address < end; address += HPAGE_SIZE) { + tlb_start_vma(tlb, vma); + mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); +again: + for (address = start; address < end; address += sz) { ptep = huge_pte_offset(mm, address); if (!ptep) continue; + ptl = huge_pte_lock(h, mm, ptep); if (huge_pmd_unshare(mm, &address, ptep)) - continue; + goto unlock; - pte = huge_ptep_get_and_clear(mm, address, ptep); - if (pte_none(pte)) - continue; + pte = huge_ptep_get(ptep); + if (huge_pte_none(pte)) + goto unlock; + + /* + * HWPoisoned hugepage is already unmapped and dropped reference + */ + if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { + huge_pte_clear(mm, address, ptep); + goto unlock; + } page = pte_page(pte); - if (pte_dirty(pte)) + /* + * If a reference page is supplied, it is because a specific + * page is being unmapped, not a range. Ensure the page we + * are about to unmap is the actual page of interest. + */ + if (ref_page) { + if (page != ref_page) + goto unlock; + + /* + * Mark the VMA as having unmapped its page so that + * future faults in this VMA will fail rather than + * looking like data was lost + */ + set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); + } + + pte = huge_ptep_get_and_clear(mm, address, ptep); + tlb_remove_tlb_entry(tlb, ptep, address); + if (huge_pte_dirty(pte)) set_page_dirty(page); - list_add(&page->lru, &page_list); + + page_remove_rmap(page); + force_flush = !__tlb_remove_page(tlb, page); + if (force_flush) { + spin_unlock(ptl); + break; + } + /* Bail out after unmapping reference page if supplied */ + if (ref_page) { + spin_unlock(ptl); + break; + } +unlock: + spin_unlock(ptl); } - spin_unlock(&mm->page_table_lock); - flush_tlb_range(vma, start, end); - list_for_each_entry_safe(page, tmp, &page_list, lru) { - list_del(&page->lru); - put_page(page); + /* + * mmu_gather ran out of room to batch pages, we break out of + * the PTE lock to avoid doing the potential expensive TLB invalidate + * and page-free while holding it. + */ + if (force_flush) { + force_flush = 0; + tlb_flush_mmu(tlb); + if (address < end && !ref_page) + goto again; } + mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); + tlb_end_vma(tlb, vma); +} + +void __unmap_hugepage_range_final(struct mmu_gather *tlb, + struct vm_area_struct *vma, unsigned long start, + unsigned long end, struct page *ref_page) +{ + __unmap_hugepage_range(tlb, vma, start, end, ref_page); + + /* + * Clear this flag so that x86's huge_pmd_share page_table_shareable + * test will fail on a vma being torn down, and not grab a page table + * on its way out. We're lucky that the flag has such an appropriate + * name, and can in fact be safely cleared here. We could clear it + * before the __unmap_hugepage_range above, but all that's necessary + * is to clear it before releasing the i_mmap_mutex. This works + * because in the context this is called, the VMA is about to be + * destroyed and the i_mmap_mutex is held. + */ + vma->vm_flags &= ~VM_MAYSHARE; } void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, - unsigned long end) + unsigned long end, struct page *ref_page) +{ + struct mm_struct *mm; + struct mmu_gather tlb; + + mm = vma->vm_mm; + + tlb_gather_mmu(&tlb, mm, start, end); + __unmap_hugepage_range(&tlb, vma, start, end, ref_page); + tlb_finish_mmu(&tlb, start, end); +} + +/* + * This is called when the original mapper is failing to COW a MAP_PRIVATE + * mappping it owns the reserve page for. The intention is to unmap the page + * from other VMAs and let the children be SIGKILLed if they are faulting the + * same region. + */ +static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, + struct page *page, unsigned long address) { + struct hstate *h = hstate_vma(vma); + struct vm_area_struct *iter_vma; + struct address_space *mapping; + pgoff_t pgoff; + /* - * It is undesirable to test vma->vm_file as it should be non-null - * for valid hugetlb area. However, vm_file will be NULL in the error - * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails, - * do_mmap_pgoff() nullifies vma->vm_file before calling this function - * to clean up. Since no pte has actually been setup, it is safe to - * do nothing in this case. + * vm_pgoff is in PAGE_SIZE units, hence the different calculation + * from page cache lookup which is in HPAGE_SIZE units. */ - if (vma->vm_file) { - spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); - __unmap_hugepage_range(vma, start, end); - spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); + address = address & huge_page_mask(h); + pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + + vma->vm_pgoff; + mapping = file_inode(vma->vm_file)->i_mapping; + + /* + * Take the mapping lock for the duration of the table walk. As + * this mapping should be shared between all the VMAs, + * __unmap_hugepage_range() is called as the lock is already held + */ + mutex_lock(&mapping->i_mmap_mutex); + vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { + /* Do not unmap the current VMA */ + if (iter_vma == vma) + continue; + + /* + * Unmap the page from other VMAs without their own reserves. + * They get marked to be SIGKILLed if they fault in these + * areas. This is because a future no-page fault on this VMA + * could insert a zeroed page instead of the data existing + * from the time of fork. This would look like data corruption + */ + if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) + unmap_hugepage_range(iter_vma, address, + address + huge_page_size(h), page); } + mutex_unlock(&mapping->i_mmap_mutex); + + return 1; } +/* + * Hugetlb_cow() should be called with page lock of the original hugepage held. + * Called with hugetlb_instantiation_mutex held and pte_page locked so we + * cannot race with other handlers or page migration. + * Keep the pte_same checks anyway to make transition from the mutex easier. + */ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long address, pte_t *ptep, pte_t pte) + unsigned long address, pte_t *ptep, pte_t pte, + struct page *pagecache_page, spinlock_t *ptl) { + struct hstate *h = hstate_vma(vma); struct page *old_page, *new_page; - int avoidcopy; + int outside_reserve = 0; + unsigned long mmun_start; /* For mmu_notifiers */ + unsigned long mmun_end; /* For mmu_notifiers */ old_page = pte_page(pte); +retry_avoidcopy: /* If no-one else is actually using this page, avoid the copy * and just make the page writable */ - avoidcopy = (page_count(old_page) == 1); - if (avoidcopy) { + if (page_mapcount(old_page) == 1 && PageAnon(old_page)) { + page_move_anon_rmap(old_page, vma, address); set_huge_ptep_writable(vma, address, ptep); return 0; } + /* + * If the process that created a MAP_PRIVATE mapping is about to + * perform a COW due to a shared page count, attempt to satisfy + * the allocation without using the existing reserves. The pagecache + * page is used to determine if the reserve at this address was + * consumed or not. If reserves were used, a partial faulted mapping + * at the time of fork() could consume its reserves on COW instead + * of the full address range. + */ + if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && + old_page != pagecache_page) + outside_reserve = 1; + page_cache_get(old_page); - new_page = alloc_huge_page(vma, address); + + /* Drop page table lock as buddy allocator may be called */ + spin_unlock(ptl); + new_page = alloc_huge_page(vma, address, outside_reserve); if (IS_ERR(new_page)) { + long err = PTR_ERR(new_page); page_cache_release(old_page); - return -PTR_ERR(new_page); + + /* + * If a process owning a MAP_PRIVATE mapping fails to COW, + * it is due to references held by a child and an insufficient + * huge page pool. To guarantee the original mappers + * reliability, unmap the page from child processes. The child + * may get SIGKILLed if it later faults. + */ + if (outside_reserve) { + BUG_ON(huge_pte_none(pte)); + if (unmap_ref_private(mm, vma, old_page, address)) { + BUG_ON(huge_pte_none(pte)); + spin_lock(ptl); + ptep = huge_pte_offset(mm, address & huge_page_mask(h)); + if (likely(ptep && + pte_same(huge_ptep_get(ptep), pte))) + goto retry_avoidcopy; + /* + * race occurs while re-acquiring page table + * lock, and our job is done. + */ + return 0; + } + WARN_ON_ONCE(1); + } + + /* Caller expects lock to be held */ + spin_lock(ptl); + if (err == -ENOMEM) + return VM_FAULT_OOM; + else + return VM_FAULT_SIGBUS; } - spin_unlock(&mm->page_table_lock); - copy_huge_page(new_page, old_page, address, vma); + /* + * When the original hugepage is shared one, it does not have + * anon_vma prepared. + */ + if (unlikely(anon_vma_prepare(vma))) { + page_cache_release(new_page); + page_cache_release(old_page); + /* Caller expects lock to be held */ + spin_lock(ptl); + return VM_FAULT_OOM; + } + + copy_user_huge_page(new_page, old_page, address, vma, + pages_per_huge_page(h)); __SetPageUptodate(new_page); - spin_lock(&mm->page_table_lock); - ptep = huge_pte_offset(mm, address & HPAGE_MASK); - if (likely(pte_same(*ptep, pte))) { + mmun_start = address & huge_page_mask(h); + mmun_end = mmun_start + huge_page_size(h); + mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); + /* + * Retake the page table lock to check for racing updates + * before the page tables are altered + */ + spin_lock(ptl); + ptep = huge_pte_offset(mm, address & huge_page_mask(h)); + if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) { + ClearPagePrivate(new_page); + /* Break COW */ + huge_ptep_clear_flush(vma, address, ptep); set_huge_pte_at(mm, address, ptep, make_huge_pte(vma, new_page, 1)); + page_remove_rmap(old_page); + hugepage_add_new_anon_rmap(new_page, vma, address); /* Make the old page be freed below */ new_page = old_page; } + spin_unlock(ptl); + mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); page_cache_release(new_page); page_cache_release(old_page); + + /* Caller expects lock to be held */ + spin_lock(ptl); return 0; } +/* Return the pagecache page at a given address within a VMA */ +static struct page *hugetlbfs_pagecache_page(struct hstate *h, + struct vm_area_struct *vma, unsigned long address) +{ + struct address_space *mapping; + pgoff_t idx; + + mapping = vma->vm_file->f_mapping; + idx = vma_hugecache_offset(h, vma, address); + + return find_lock_page(mapping, idx); +} + +/* + * Return whether there is a pagecache page to back given address within VMA. + * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. + */ +static bool hugetlbfs_pagecache_present(struct hstate *h, + struct vm_area_struct *vma, unsigned long address) +{ + struct address_space *mapping; + pgoff_t idx; + struct page *page; + + mapping = vma->vm_file->f_mapping; + idx = vma_hugecache_offset(h, vma, address); + + page = find_get_page(mapping, idx); + if (page) + put_page(page); + return page != NULL; +} + static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long address, pte_t *ptep, int write_access) + struct address_space *mapping, pgoff_t idx, + unsigned long address, pte_t *ptep, unsigned int flags) { + struct hstate *h = hstate_vma(vma); int ret = VM_FAULT_SIGBUS; - unsigned long idx; + int anon_rmap = 0; unsigned long size; struct page *page; - struct address_space *mapping; pte_t new_pte; + spinlock_t *ptl; - mapping = vma->vm_file->f_mapping; - idx = ((address - vma->vm_start) >> HPAGE_SHIFT) - + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); + /* + * Currently, we are forced to kill the process in the event the + * original mapper has unmapped pages from the child due to a failed + * COW. Warn that such a situation has occurred as it may not be obvious + */ + if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { + pr_warning("PID %d killed due to inadequate hugepage pool\n", + current->pid); + return ret; + } /* * Use page lock to guard against racing truncation @@ -906,18 +2991,22 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, retry: page = find_lock_page(mapping, idx); if (!page) { - size = i_size_read(mapping->host) >> HPAGE_SHIFT; + size = i_size_read(mapping->host) >> huge_page_shift(h); if (idx >= size) goto out; - page = alloc_huge_page(vma, address); + page = alloc_huge_page(vma, address, 0); if (IS_ERR(page)) { - ret = -PTR_ERR(page); + ret = PTR_ERR(page); + if (ret == -ENOMEM) + ret = VM_FAULT_OOM; + else + ret = VM_FAULT_SIGBUS; goto out; } - clear_huge_page(page, address); + clear_huge_page(page, address, pages_per_huge_page(h)); __SetPageUptodate(page); - if (vma->vm_flags & VM_SHARED) { + if (vma->vm_flags & VM_MAYSHARE) { int err; struct inode *inode = mapping->host; @@ -928,124 +3017,307 @@ retry: goto retry; goto out; } + ClearPagePrivate(page); spin_lock(&inode->i_lock); - inode->i_blocks += BLOCKS_PER_HUGEPAGE; + inode->i_blocks += blocks_per_huge_page(h); spin_unlock(&inode->i_lock); - } else + } else { lock_page(page); + if (unlikely(anon_vma_prepare(vma))) { + ret = VM_FAULT_OOM; + goto backout_unlocked; + } + anon_rmap = 1; + } + } else { + /* + * If memory error occurs between mmap() and fault, some process + * don't have hwpoisoned swap entry for errored virtual address. + * So we need to block hugepage fault by PG_hwpoison bit check. + */ + if (unlikely(PageHWPoison(page))) { + ret = VM_FAULT_HWPOISON | + VM_FAULT_SET_HINDEX(hstate_index(h)); + goto backout_unlocked; + } } - spin_lock(&mm->page_table_lock); - size = i_size_read(mapping->host) >> HPAGE_SHIFT; + /* + * If we are going to COW a private mapping later, we examine the + * pending reservations for this page now. This will ensure that + * any allocations necessary to record that reservation occur outside + * the spinlock. + */ + if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) + if (vma_needs_reservation(h, vma, address) < 0) { + ret = VM_FAULT_OOM; + goto backout_unlocked; + } + + ptl = huge_pte_lockptr(h, mm, ptep); + spin_lock(ptl); + size = i_size_read(mapping->host) >> huge_page_shift(h); if (idx >= size) goto backout; ret = 0; - if (!pte_none(*ptep)) + if (!huge_pte_none(huge_ptep_get(ptep))) goto backout; + if (anon_rmap) { + ClearPagePrivate(page); + hugepage_add_new_anon_rmap(page, vma, address); + } else + page_dup_rmap(page); new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_SHARED))); set_huge_pte_at(mm, address, ptep, new_pte); - if (write_access && !(vma->vm_flags & VM_SHARED)) { + if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { /* Optimization, do the COW without a second fault */ - ret = hugetlb_cow(mm, vma, address, ptep, new_pte); + ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl); } - spin_unlock(&mm->page_table_lock); + spin_unlock(ptl); unlock_page(page); out: return ret; backout: - spin_unlock(&mm->page_table_lock); + spin_unlock(ptl); +backout_unlocked: unlock_page(page); put_page(page); goto out; } +#ifdef CONFIG_SMP +static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, + struct vm_area_struct *vma, + struct address_space *mapping, + pgoff_t idx, unsigned long address) +{ + unsigned long key[2]; + u32 hash; + + if (vma->vm_flags & VM_SHARED) { + key[0] = (unsigned long) mapping; + key[1] = idx; + } else { + key[0] = (unsigned long) mm; + key[1] = address >> huge_page_shift(h); + } + + hash = jhash2((u32 *)&key, sizeof(key)/sizeof(u32), 0); + + return hash & (num_fault_mutexes - 1); +} +#else +/* + * For uniprocesor systems we always use a single mutex, so just + * return 0 and avoid the hashing overhead. + */ +static u32 fault_mutex_hash(struct hstate *h, struct mm_struct *mm, + struct vm_area_struct *vma, + struct address_space *mapping, + pgoff_t idx, unsigned long address) +{ + return 0; +} +#endif + int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long address, int write_access) + unsigned long address, unsigned int flags) { - pte_t *ptep; - pte_t entry; + pte_t *ptep, entry; + spinlock_t *ptl; int ret; - static DEFINE_MUTEX(hugetlb_instantiation_mutex); + u32 hash; + pgoff_t idx; + struct page *page = NULL; + struct page *pagecache_page = NULL; + struct hstate *h = hstate_vma(vma); + struct address_space *mapping; + + address &= huge_page_mask(h); + + ptep = huge_pte_offset(mm, address); + if (ptep) { + entry = huge_ptep_get(ptep); + if (unlikely(is_hugetlb_entry_migration(entry))) { + migration_entry_wait_huge(vma, mm, ptep); + return 0; + } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) + return VM_FAULT_HWPOISON_LARGE | + VM_FAULT_SET_HINDEX(hstate_index(h)); + } - ptep = huge_pte_alloc(mm, address); + ptep = huge_pte_alloc(mm, address, huge_page_size(h)); if (!ptep) return VM_FAULT_OOM; + mapping = vma->vm_file->f_mapping; + idx = vma_hugecache_offset(h, vma, address); + /* * Serialize hugepage allocation and instantiation, so that we don't * get spurious allocation failures if two CPUs race to instantiate * the same page in the page cache. */ - mutex_lock(&hugetlb_instantiation_mutex); - entry = *ptep; - if (pte_none(entry)) { - ret = hugetlb_no_page(mm, vma, address, ptep, write_access); - mutex_unlock(&hugetlb_instantiation_mutex); - return ret; + hash = fault_mutex_hash(h, mm, vma, mapping, idx, address); + mutex_lock(&htlb_fault_mutex_table[hash]); + + entry = huge_ptep_get(ptep); + if (huge_pte_none(entry)) { + ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags); + goto out_mutex; } ret = 0; - spin_lock(&mm->page_table_lock); + /* + * If we are going to COW the mapping later, we examine the pending + * reservations for this page now. This will ensure that any + * allocations necessary to record that reservation occur outside the + * spinlock. For private mappings, we also lookup the pagecache + * page now as it is used to determine if a reservation has been + * consumed. + */ + if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { + if (vma_needs_reservation(h, vma, address) < 0) { + ret = VM_FAULT_OOM; + goto out_mutex; + } + + if (!(vma->vm_flags & VM_MAYSHARE)) + pagecache_page = hugetlbfs_pagecache_page(h, + vma, address); + } + + /* + * hugetlb_cow() requires page locks of pte_page(entry) and + * pagecache_page, so here we need take the former one + * when page != pagecache_page or !pagecache_page. + * Note that locking order is always pagecache_page -> page, + * so no worry about deadlock. + */ + page = pte_page(entry); + get_page(page); + if (page != pagecache_page) + lock_page(page); + + ptl = huge_pte_lockptr(h, mm, ptep); + spin_lock(ptl); /* Check for a racing update before calling hugetlb_cow */ - if (likely(pte_same(entry, *ptep))) - if (write_access && !pte_write(entry)) - ret = hugetlb_cow(mm, vma, address, ptep, entry); - spin_unlock(&mm->page_table_lock); - mutex_unlock(&hugetlb_instantiation_mutex); + if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) + goto out_ptl; + + + if (flags & FAULT_FLAG_WRITE) { + if (!huge_pte_write(entry)) { + ret = hugetlb_cow(mm, vma, address, ptep, entry, + pagecache_page, ptl); + goto out_ptl; + } + entry = huge_pte_mkdirty(entry); + } + entry = pte_mkyoung(entry); + if (huge_ptep_set_access_flags(vma, address, ptep, entry, + flags & FAULT_FLAG_WRITE)) + update_mmu_cache(vma, address, ptep); +out_ptl: + spin_unlock(ptl); + + if (pagecache_page) { + unlock_page(pagecache_page); + put_page(pagecache_page); + } + if (page != pagecache_page) + unlock_page(page); + put_page(page); + +out_mutex: + mutex_unlock(&htlb_fault_mutex_table[hash]); return ret; } -int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, - struct page **pages, struct vm_area_struct **vmas, - unsigned long *position, int *length, int i, - int write) +long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, + struct page **pages, struct vm_area_struct **vmas, + unsigned long *position, unsigned long *nr_pages, + long i, unsigned int flags) { unsigned long pfn_offset; unsigned long vaddr = *position; - int remainder = *length; + unsigned long remainder = *nr_pages; + struct hstate *h = hstate_vma(vma); - spin_lock(&mm->page_table_lock); while (vaddr < vma->vm_end && remainder) { pte_t *pte; + spinlock_t *ptl = NULL; + int absent; struct page *page; /* * Some archs (sparc64, sh*) have multiple pte_ts to - * each hugepage. We have to make * sure we get the + * each hugepage. We have to make sure we get the * first, for the page indexing below to work. + * + * Note that page table lock is not held when pte is null. + */ + pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); + if (pte) + ptl = huge_pte_lock(h, mm, pte); + absent = !pte || huge_pte_none(huge_ptep_get(pte)); + + /* + * When coredumping, it suits get_dump_page if we just return + * an error where there's an empty slot with no huge pagecache + * to back it. This way, we avoid allocating a hugepage, and + * the sparse dumpfile avoids allocating disk blocks, but its + * huge holes still show up with zeroes where they need to be. */ - pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); + if (absent && (flags & FOLL_DUMP) && + !hugetlbfs_pagecache_present(h, vma, vaddr)) { + if (pte) + spin_unlock(ptl); + remainder = 0; + break; + } - if (!pte || pte_none(*pte) || (write && !pte_write(*pte))) { + /* + * We need call hugetlb_fault for both hugepages under migration + * (in which case hugetlb_fault waits for the migration,) and + * hwpoisoned hugepages (in which case we need to prevent the + * caller from accessing to them.) In order to do this, we use + * here is_swap_pte instead of is_hugetlb_entry_migration and + * is_hugetlb_entry_hwpoisoned. This is because it simply covers + * both cases, and because we can't follow correct pages + * directly from any kind of swap entries. + */ + if (absent || is_swap_pte(huge_ptep_get(pte)) || + ((flags & FOLL_WRITE) && + !huge_pte_write(huge_ptep_get(pte)))) { int ret; - spin_unlock(&mm->page_table_lock); - ret = hugetlb_fault(mm, vma, vaddr, write); - spin_lock(&mm->page_table_lock); + if (pte) + spin_unlock(ptl); + ret = hugetlb_fault(mm, vma, vaddr, + (flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0); if (!(ret & VM_FAULT_ERROR)) continue; remainder = 0; - if (!i) - i = -EFAULT; break; } - pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; - page = pte_page(*pte); + pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; + page = pte_page(huge_ptep_get(pte)); same_page: if (pages) { - get_page(page); - pages[i] = page + pfn_offset; + pages[i] = mem_map_offset(page, pfn_offset); + get_page_foll(pages[i]); } if (vmas) @@ -1056,241 +3328,462 @@ same_page: --remainder; ++i; if (vaddr < vma->vm_end && remainder && - pfn_offset < HPAGE_SIZE/PAGE_SIZE) { + pfn_offset < pages_per_huge_page(h)) { /* * We use pfn_offset to avoid touching the pageframes * of this compound page. */ goto same_page; } + spin_unlock(ptl); } - spin_unlock(&mm->page_table_lock); - *length = remainder; + *nr_pages = remainder; *position = vaddr; - return i; + return i ? i : -EFAULT; } -void hugetlb_change_protection(struct vm_area_struct *vma, +unsigned long hugetlb_change_protection(struct vm_area_struct *vma, unsigned long address, unsigned long end, pgprot_t newprot) { struct mm_struct *mm = vma->vm_mm; unsigned long start = address; pte_t *ptep; pte_t pte; + struct hstate *h = hstate_vma(vma); + unsigned long pages = 0; BUG_ON(address >= end); flush_cache_range(vma, address, end); - spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); - spin_lock(&mm->page_table_lock); - for (; address < end; address += HPAGE_SIZE) { + mmu_notifier_invalidate_range_start(mm, start, end); + mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); + for (; address < end; address += huge_page_size(h)) { + spinlock_t *ptl; ptep = huge_pte_offset(mm, address); if (!ptep) continue; - if (huge_pmd_unshare(mm, &address, ptep)) + ptl = huge_pte_lock(h, mm, ptep); + if (huge_pmd_unshare(mm, &address, ptep)) { + pages++; + spin_unlock(ptl); continue; - if (!pte_none(*ptep)) { + } + if (!huge_pte_none(huge_ptep_get(ptep))) { pte = huge_ptep_get_and_clear(mm, address, ptep); - pte = pte_mkhuge(pte_modify(pte, newprot)); + pte = pte_mkhuge(huge_pte_modify(pte, newprot)); + pte = arch_make_huge_pte(pte, vma, NULL, 0); set_huge_pte_at(mm, address, ptep, pte); + pages++; } + spin_unlock(ptl); } - spin_unlock(&mm->page_table_lock); - spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); - + /* + * Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare + * may have cleared our pud entry and done put_page on the page table: + * once we release i_mmap_mutex, another task can do the final put_page + * and that page table be reused and filled with junk. + */ flush_tlb_range(vma, start, end); -} + mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); + mmu_notifier_invalidate_range_end(mm, start, end); -struct file_region { - struct list_head link; - long from; - long to; -}; + return pages << h->order; +} -static long region_add(struct list_head *head, long f, long t) +int hugetlb_reserve_pages(struct inode *inode, + long from, long to, + struct vm_area_struct *vma, + vm_flags_t vm_flags) { - struct file_region *rg, *nrg, *trg; + long ret, chg; + struct hstate *h = hstate_inode(inode); + struct hugepage_subpool *spool = subpool_inode(inode); + struct resv_map *resv_map; - /* Locate the region we are either in or before. */ - list_for_each_entry(rg, head, link) - if (f <= rg->to) - break; + /* + * Only apply hugepage reservation if asked. At fault time, an + * attempt will be made for VM_NORESERVE to allocate a page + * without using reserves + */ + if (vm_flags & VM_NORESERVE) + return 0; - /* Round our left edge to the current segment if it encloses us. */ - if (f > rg->from) - f = rg->from; + /* + * Shared mappings base their reservation on the number of pages that + * are already allocated on behalf of the file. Private mappings need + * to reserve the full area even if read-only as mprotect() may be + * called to make the mapping read-write. Assume !vma is a shm mapping + */ + if (!vma || vma->vm_flags & VM_MAYSHARE) { + resv_map = inode_resv_map(inode); - /* Check for and consume any regions we now overlap with. */ - nrg = rg; - list_for_each_entry_safe(rg, trg, rg->link.prev, link) { - if (&rg->link == head) - break; - if (rg->from > t) - break; + chg = region_chg(resv_map, from, to); - /* If this area reaches higher then extend our area to - * include it completely. If this is not the first area - * which we intend to reuse, free it. */ - if (rg->to > t) - t = rg->to; - if (rg != nrg) { - list_del(&rg->link); - kfree(rg); - } + } else { + resv_map = resv_map_alloc(); + if (!resv_map) + return -ENOMEM; + + chg = to - from; + + set_vma_resv_map(vma, resv_map); + set_vma_resv_flags(vma, HPAGE_RESV_OWNER); } - nrg->from = f; - nrg->to = t; + + if (chg < 0) { + ret = chg; + goto out_err; + } + + /* There must be enough pages in the subpool for the mapping */ + if (hugepage_subpool_get_pages(spool, chg)) { + ret = -ENOSPC; + goto out_err; + } + + /* + * Check enough hugepages are available for the reservation. + * Hand the pages back to the subpool if there are not + */ + ret = hugetlb_acct_memory(h, chg); + if (ret < 0) { + hugepage_subpool_put_pages(spool, chg); + goto out_err; + } + + /* + * Account for the reservations made. Shared mappings record regions + * that have reservations as they are shared by multiple VMAs. + * When the last VMA disappears, the region map says how much + * the reservation was and the page cache tells how much of + * the reservation was consumed. Private mappings are per-VMA and + * only the consumed reservations are tracked. When the VMA + * disappears, the original reservation is the VMA size and the + * consumed reservations are stored in the map. Hence, nothing + * else has to be done for private mappings here + */ + if (!vma || vma->vm_flags & VM_MAYSHARE) + region_add(resv_map, from, to); return 0; +out_err: + if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) + kref_put(&resv_map->refs, resv_map_release); + return ret; } -static long region_chg(struct list_head *head, long f, long t) +void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) { - struct file_region *rg, *nrg; + struct hstate *h = hstate_inode(inode); + struct resv_map *resv_map = inode_resv_map(inode); long chg = 0; + struct hugepage_subpool *spool = subpool_inode(inode); - /* Locate the region we are before or in. */ - list_for_each_entry(rg, head, link) - if (f <= rg->to) - break; + if (resv_map) + chg = region_truncate(resv_map, offset); + spin_lock(&inode->i_lock); + inode->i_blocks -= (blocks_per_huge_page(h) * freed); + spin_unlock(&inode->i_lock); - /* If we are below the current region then a new region is required. - * Subtle, allocate a new region at the position but make it zero - * size such that we can guarantee to record the reservation. */ - if (&rg->link == head || t < rg->from) { - nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); - if (!nrg) - return -ENOMEM; - nrg->from = f; - nrg->to = f; - INIT_LIST_HEAD(&nrg->link); - list_add(&nrg->link, rg->link.prev); + hugepage_subpool_put_pages(spool, (chg - freed)); + hugetlb_acct_memory(h, -(chg - freed)); +} - return t - f; - } +#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE +static unsigned long page_table_shareable(struct vm_area_struct *svma, + struct vm_area_struct *vma, + unsigned long addr, pgoff_t idx) +{ + unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + + svma->vm_start; + unsigned long sbase = saddr & PUD_MASK; + unsigned long s_end = sbase + PUD_SIZE; - /* Round our left edge to the current segment if it encloses us. */ - if (f > rg->from) - f = rg->from; - chg = t - f; + /* Allow segments to share if only one is marked locked */ + unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED; + unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED; - /* Check for and consume any regions we now overlap with. */ - list_for_each_entry(rg, rg->link.prev, link) { - if (&rg->link == head) - break; - if (rg->from > t) - return chg; + /* + * match the virtual addresses, permission and the alignment of the + * page table page. + */ + if (pmd_index(addr) != pmd_index(saddr) || + vm_flags != svm_flags || + sbase < svma->vm_start || svma->vm_end < s_end) + return 0; - /* We overlap with this area, if it extends futher than - * us then we must extend ourselves. Account for its - * existing reservation. */ - if (rg->to > t) { - chg += rg->to - t; - t = rg->to; + return saddr; +} + +static int vma_shareable(struct vm_area_struct *vma, unsigned long addr) +{ + unsigned long base = addr & PUD_MASK; + unsigned long end = base + PUD_SIZE; + + /* + * check on proper vm_flags and page table alignment + */ + if (vma->vm_flags & VM_MAYSHARE && + vma->vm_start <= base && end <= vma->vm_end) + return 1; + return 0; +} + +/* + * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() + * and returns the corresponding pte. While this is not necessary for the + * !shared pmd case because we can allocate the pmd later as well, it makes the + * code much cleaner. pmd allocation is essential for the shared case because + * pud has to be populated inside the same i_mmap_mutex section - otherwise + * racing tasks could either miss the sharing (see huge_pte_offset) or select a + * bad pmd for sharing. + */ +pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) +{ + struct vm_area_struct *vma = find_vma(mm, addr); + struct address_space *mapping = vma->vm_file->f_mapping; + pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + + vma->vm_pgoff; + struct vm_area_struct *svma; + unsigned long saddr; + pte_t *spte = NULL; + pte_t *pte; + spinlock_t *ptl; + + if (!vma_shareable(vma, addr)) + return (pte_t *)pmd_alloc(mm, pud, addr); + + mutex_lock(&mapping->i_mmap_mutex); + vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { + if (svma == vma) + continue; + + saddr = page_table_shareable(svma, vma, addr, idx); + if (saddr) { + spte = huge_pte_offset(svma->vm_mm, saddr); + if (spte) { + get_page(virt_to_page(spte)); + break; + } } - chg -= rg->to - rg->from; } - return chg; + + if (!spte) + goto out; + + ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte); + spin_lock(ptl); + if (pud_none(*pud)) + pud_populate(mm, pud, + (pmd_t *)((unsigned long)spte & PAGE_MASK)); + else + put_page(virt_to_page(spte)); + spin_unlock(ptl); +out: + pte = (pte_t *)pmd_alloc(mm, pud, addr); + mutex_unlock(&mapping->i_mmap_mutex); + return pte; } -static long region_truncate(struct list_head *head, long end) +/* + * unmap huge page backed by shared pte. + * + * Hugetlb pte page is ref counted at the time of mapping. If pte is shared + * indicated by page_count > 1, unmap is achieved by clearing pud and + * decrementing the ref count. If count == 1, the pte page is not shared. + * + * called with page table lock held. + * + * returns: 1 successfully unmapped a shared pte page + * 0 the underlying pte page is not shared, or it is the last user + */ +int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) { - struct file_region *rg, *trg; - long chg = 0; + pgd_t *pgd = pgd_offset(mm, *addr); + pud_t *pud = pud_offset(pgd, *addr); - /* Locate the region we are either in or before. */ - list_for_each_entry(rg, head, link) - if (end <= rg->to) - break; - if (&rg->link == head) + BUG_ON(page_count(virt_to_page(ptep)) == 0); + if (page_count(virt_to_page(ptep)) == 1) return 0; - /* If we are in the middle of a region then adjust it. */ - if (end > rg->from) { - chg = rg->to - end; - rg->to = end; - rg = list_entry(rg->link.next, typeof(*rg), link); + pud_clear(pud); + put_page(virt_to_page(ptep)); + *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE; + return 1; +} +#define want_pmd_share() (1) +#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ +pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) +{ + return NULL; +} +#define want_pmd_share() (0) +#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ + +#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB +pte_t *huge_pte_alloc(struct mm_struct *mm, + unsigned long addr, unsigned long sz) +{ + pgd_t *pgd; + pud_t *pud; + pte_t *pte = NULL; + + pgd = pgd_offset(mm, addr); + pud = pud_alloc(mm, pgd, addr); + if (pud) { + if (sz == PUD_SIZE) { + pte = (pte_t *)pud; + } else { + BUG_ON(sz != PMD_SIZE); + if (want_pmd_share() && pud_none(*pud)) + pte = huge_pmd_share(mm, addr, pud); + else + pte = (pte_t *)pmd_alloc(mm, pud, addr); + } } + BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)); - /* Drop any remaining regions. */ - list_for_each_entry_safe(rg, trg, rg->link.prev, link) { - if (&rg->link == head) - break; - chg += rg->to - rg->from; - list_del(&rg->link); - kfree(rg); + return pte; +} + +pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd = NULL; + + pgd = pgd_offset(mm, addr); + if (pgd_present(*pgd)) { + pud = pud_offset(pgd, addr); + if (pud_present(*pud)) { + if (pud_huge(*pud)) + return (pte_t *)pud; + pmd = pmd_offset(pud, addr); + } } - return chg; + return (pte_t *) pmd; } -static int hugetlb_acct_memory(long delta) +struct page * +follow_huge_pmd(struct mm_struct *mm, unsigned long address, + pmd_t *pmd, int write) { - int ret = -ENOMEM; + struct page *page; - spin_lock(&hugetlb_lock); - /* - * When cpuset is configured, it breaks the strict hugetlb page - * reservation as the accounting is done on a global variable. Such - * reservation is completely rubbish in the presence of cpuset because - * the reservation is not checked against page availability for the - * current cpuset. Application can still potentially OOM'ed by kernel - * with lack of free htlb page in cpuset that the task is in. - * Attempt to enforce strict accounting with cpuset is almost - * impossible (or too ugly) because cpuset is too fluid that - * task or memory node can be dynamically moved between cpusets. - * - * The change of semantics for shared hugetlb mapping with cpuset is - * undesirable. However, in order to preserve some of the semantics, - * we fall back to check against current free page availability as - * a best attempt and hopefully to minimize the impact of changing - * semantics that cpuset has. - */ - if (delta > 0) { - if (gather_surplus_pages(delta) < 0) - goto out; + page = pte_page(*(pte_t *)pmd); + if (page) + page += ((address & ~PMD_MASK) >> PAGE_SHIFT); + return page; +} - if (delta > cpuset_mems_nr(free_huge_pages_node)) { - return_unused_surplus_pages(delta); - goto out; - } - } +struct page * +follow_huge_pud(struct mm_struct *mm, unsigned long address, + pud_t *pud, int write) +{ + struct page *page; - ret = 0; - if (delta < 0) - return_unused_surplus_pages((unsigned long) -delta); + page = pte_page(*(pte_t *)pud); + if (page) + page += ((address & ~PUD_MASK) >> PAGE_SHIFT); + return page; +} -out: - spin_unlock(&hugetlb_lock); - return ret; +#else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ + +/* Can be overriden by architectures */ +struct page * __weak +follow_huge_pud(struct mm_struct *mm, unsigned long address, + pud_t *pud, int write) +{ + BUG(); + return NULL; } -int hugetlb_reserve_pages(struct inode *inode, long from, long to) +#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ + +#ifdef CONFIG_MEMORY_FAILURE + +/* Should be called in hugetlb_lock */ +static int is_hugepage_on_freelist(struct page *hpage) { - long ret, chg; + struct page *page; + struct page *tmp; + struct hstate *h = page_hstate(hpage); + int nid = page_to_nid(hpage); - chg = region_chg(&inode->i_mapping->private_list, from, to); - if (chg < 0) - return chg; + list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) + if (page == hpage) + return 1; + return 0; +} - if (hugetlb_get_quota(inode->i_mapping, chg)) - return -ENOSPC; - ret = hugetlb_acct_memory(chg); - if (ret < 0) { - hugetlb_put_quota(inode->i_mapping, chg); - return ret; +/* + * This function is called from memory failure code. + * Assume the caller holds page lock of the head page. + */ +int dequeue_hwpoisoned_huge_page(struct page *hpage) +{ + struct hstate *h = page_hstate(hpage); + int nid = page_to_nid(hpage); + int ret = -EBUSY; + + spin_lock(&hugetlb_lock); + if (is_hugepage_on_freelist(hpage)) { + /* + * Hwpoisoned hugepage isn't linked to activelist or freelist, + * but dangling hpage->lru can trigger list-debug warnings + * (this happens when we call unpoison_memory() on it), + * so let it point to itself with list_del_init(). + */ + list_del_init(&hpage->lru); + set_page_refcounted(hpage); + h->free_huge_pages--; + h->free_huge_pages_node[nid]--; + ret = 0; } - region_add(&inode->i_mapping->private_list, from, to); - return 0; + spin_unlock(&hugetlb_lock); + return ret; } +#endif -void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) +bool isolate_huge_page(struct page *page, struct list_head *list) { - long chg = region_truncate(&inode->i_mapping->private_list, offset); + VM_BUG_ON_PAGE(!PageHead(page), page); + if (!get_page_unless_zero(page)) + return false; + spin_lock(&hugetlb_lock); + list_move_tail(&page->lru, list); + spin_unlock(&hugetlb_lock); + return true; +} - spin_lock(&inode->i_lock); - inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed; - spin_unlock(&inode->i_lock); +void putback_active_hugepage(struct page *page) +{ + VM_BUG_ON_PAGE(!PageHead(page), page); + spin_lock(&hugetlb_lock); + list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist); + spin_unlock(&hugetlb_lock); + put_page(page); +} - hugetlb_put_quota(inode->i_mapping, (chg - freed)); - hugetlb_acct_memory(-(chg - freed)); +bool is_hugepage_active(struct page *page) +{ + VM_BUG_ON_PAGE(!PageHuge(page), page); + /* + * This function can be called for a tail page because the caller, + * scan_movable_pages, scans through a given pfn-range which typically + * covers one memory block. In systems using gigantic hugepage (1GB + * for x86_64,) a hugepage is larger than a memory block, and we don't + * support migrating such large hugepages for now, so return false + * when called for tail pages. + */ + if (PageTail(page)) + return false; + /* + * Refcount of a hwpoisoned hugepages is 1, but they are not active, + * so we should return false for them. + */ + if (unlikely(PageHWPoison(page))) + return false; + return page_count(page) > 0; } |