| /* |
| * Generic hugetlb support. |
| * (C) William Irwin, 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/cpuset.h> |
| #include <linux/mutex.h> |
| #include <linux/bootmem.h> |
| #include <linux/sysfs.h> |
| |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| #include <asm/io.h> |
| |
| #include <linux/hugetlb.h> |
| #include "internal.h" |
| |
| const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; |
| static gfp_t htlb_alloc_mask = GFP_HIGHUSER; |
| unsigned long hugepages_treat_as_movable; |
| |
| static int max_hstate; |
| unsigned int default_hstate_idx; |
| struct hstate hstates[HUGE_MAX_HSTATE]; |
| |
| __initdata LIST_HEAD(huge_boot_pages); |
| |
| /* for command line parsing */ |
| static struct hstate * __initdata parsed_hstate; |
| static unsigned long __initdata default_hstate_max_huge_pages; |
| static unsigned long __initdata default_hstate_size; |
| |
| #define for_each_hstate(h) \ |
| for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++) |
| |
| /* |
| * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages |
| */ |
| static DEFINE_SPINLOCK(hugetlb_lock); |
| |
| /* |
| * Region tracking -- allows tracking of reservations and instantiated pages |
| * across the pages in a mapping. |
| * |
| * The region data structures are protected by a combination of the mmap_sem |
| * and the hugetlb_instantion_mutex. To access or modify a region the caller |
| * must either hold the mmap_sem for write, or the mmap_sem for read and |
| * the hugetlb_instantiation mutex: |
| * |
| * down_write(&mm->mmap_sem); |
| * or |
| * down_read(&mm->mmap_sem); |
| * mutex_lock(&hugetlb_instantiation_mutex); |
| */ |
| struct file_region { |
| struct list_head link; |
| long from; |
| long to; |
| }; |
| |
| static long region_add(struct list_head *head, long f, long t) |
| { |
| struct file_region *rg, *nrg, *trg; |
| |
| /* Locate the region we are either in or before. */ |
| list_for_each_entry(rg, head, link) |
| if (f <= rg->to) |
| break; |
| |
| /* Round our left edge to the current segment if it encloses us. */ |
| if (f > rg->from) |
| f = rg->from; |
| |
| /* Check for and consume any regions we now overlap with. */ |
| nrg = rg; |
| list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
| if (&rg->link == head) |
| break; |
| if (rg->from > t) |
| break; |
| |
| /* If this area reaches higher then extend our area to |
| * include it completely. If this is not the first area |
| * which we intend to reuse, free it. */ |
| if (rg->to > t) |
| t = rg->to; |
| if (rg != nrg) { |
| list_del(&rg->link); |
| kfree(rg); |
| } |
| } |
| nrg->from = f; |
| nrg->to = t; |
| return 0; |
| } |
| |
| static long region_chg(struct list_head *head, long f, long t) |
| { |
| struct file_region *rg, *nrg; |
| long chg = 0; |
| |
| /* Locate the region we are before or in. */ |
| list_for_each_entry(rg, head, link) |
| if (f <= rg->to) |
| break; |
| |
| /* If we are below the current region then a new region is required. |
| * Subtle, allocate a new region at the position but make it zero |
| * size such that we can guarantee to record the reservation. */ |
| if (&rg->link == head || t < rg->from) { |
| nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
| if (!nrg) |
| return -ENOMEM; |
| nrg->from = f; |
| nrg->to = f; |
| INIT_LIST_HEAD(&nrg->link); |
| list_add(&nrg->link, rg->link.prev); |
| |
| return t - f; |
| } |
| |
| /* Round our left edge to the current segment if it encloses us. */ |
| if (f > rg->from) |
| f = rg->from; |
| chg = t - f; |
| |
| /* Check for and consume any regions we now overlap with. */ |
| list_for_each_entry(rg, rg->link.prev, link) { |
| if (&rg->link == head) |
| break; |
| if (rg->from > t) |
| return chg; |
| |
| /* We overlap with this area, if it extends futher than |
| * us then we must extend ourselves. Account for its |
| * existing reservation. */ |
| if (rg->to > t) { |
| chg += rg->to - t; |
| t = rg->to; |
| } |
| chg -= rg->to - rg->from; |
| } |
| return chg; |
| } |
| |
| static long region_truncate(struct list_head *head, long end) |
| { |
| struct file_region *rg, *trg; |
| long chg = 0; |
| |
| /* Locate the region we are either in or before. */ |
| list_for_each_entry(rg, head, link) |
| if (end <= rg->to) |
| break; |
| if (&rg->link == head) |
| return 0; |
| |
| /* If we are in the middle of a region then adjust it. */ |
| if (end > rg->from) { |
| chg = rg->to - end; |
| rg->to = end; |
| rg = list_entry(rg->link.next, typeof(*rg), link); |
| } |
| |
| /* Drop any remaining regions. */ |
| list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
| if (&rg->link == head) |
| break; |
| chg += rg->to - rg->from; |
| list_del(&rg->link); |
| kfree(rg); |
| } |
| return chg; |
| } |
| |
| static long region_count(struct list_head *head, long f, long t) |
| { |
| struct file_region *rg; |
| long chg = 0; |
| |
| /* Locate each segment we overlap with, and count that overlap. */ |
| list_for_each_entry(rg, head, link) { |
| int seg_from; |
| int seg_to; |
| |
| if (rg->to <= f) |
| continue; |
| if (rg->from >= t) |
| break; |
| |
| seg_from = max(rg->from, f); |
| seg_to = min(rg->to, t); |
| |
| chg += seg_to - seg_from; |
| } |
| |
| return chg; |
| } |
| |
| /* |
| * Convert the address within this vma to the page offset within |
| * the mapping, in pagecache page units; huge pages here. |
| */ |
| static pgoff_t vma_hugecache_offset(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long address) |
| { |
| return ((address - vma->vm_start) >> huge_page_shift(h)) + |
| (vma->vm_pgoff >> huge_page_order(h)); |
| } |
| |
| /* |
| * Return the size of the pages allocated when backing a VMA. In the majority |
| * cases this will be same size as used by the page table entries. |
| */ |
| unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) |
| { |
| struct hstate *hstate; |
| |
| if (!is_vm_hugetlb_page(vma)) |
| return PAGE_SIZE; |
| |
| hstate = hstate_vma(vma); |
| |
| return 1UL << (hstate->order + PAGE_SHIFT); |
| } |
| |
| /* |
| * Return the page size being used by the MMU to back a VMA. In the majority |
| * of cases, the page size used by the kernel matches the MMU size. On |
| * architectures where it differs, an architecture-specific version of this |
| * function is required. |
| */ |
| #ifndef vma_mmu_pagesize |
| unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) |
| { |
| return vma_kernel_pagesize(vma); |
| } |
| #endif |
| |
| /* |
| * Flags for MAP_PRIVATE reservations. These are stored in the bottom |
| * bits of the reservation map pointer, which are always clear due to |
| * alignment. |
| */ |
| #define HPAGE_RESV_OWNER (1UL << 0) |
| #define HPAGE_RESV_UNMAPPED (1UL << 1) |
| #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) |
| |
| /* |
| * These helpers are used to track how many pages are reserved for |
| * faults in a MAP_PRIVATE mapping. Only the process that called mmap() |
| * is guaranteed to have their future faults succeed. |
| * |
| * With the exception of reset_vma_resv_huge_pages() which is called at fork(), |
| * the reserve counters are updated with the hugetlb_lock held. It is safe |
| * to reset the VMA at fork() time as it is not in use yet and there is no |
| * chance of the global counters getting corrupted as a result of the values. |
| * |
| * The private mapping reservation is represented in a subtly different |
| * manner to a shared mapping. A shared mapping has a region map associated |
| * with the underlying file, this region map represents the backing file |
| * pages which have ever had a reservation assigned which this persists even |
| * after the page is instantiated. A private mapping has a region map |
| * associated with the original mmap which is attached to all VMAs which |
| * reference it, this region map represents those offsets which have consumed |
| * reservation ie. where pages have been instantiated. |
| */ |
| static unsigned long get_vma_private_data(struct vm_area_struct *vma) |
| { |
| return (unsigned long)vma->vm_private_data; |
| } |
| |
| static void set_vma_private_data(struct vm_area_struct *vma, |
| unsigned long value) |
| { |
| vma->vm_private_data = (void *)value; |
| } |
| |
| struct resv_map { |
| struct kref refs; |
| struct list_head regions; |
| }; |
| |
| static struct resv_map *resv_map_alloc(void) |
| { |
| struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); |
| if (!resv_map) |
| return NULL; |
| |
| kref_init(&resv_map->refs); |
| INIT_LIST_HEAD(&resv_map->regions); |
| |
| return resv_map; |
| } |
| |
| static void resv_map_release(struct kref *ref) |
| { |
| struct resv_map *resv_map = container_of(ref, struct resv_map, refs); |
| |
| /* Clear out any active regions before we release the map. */ |
| region_truncate(&resv_map->regions, 0); |
| kfree(resv_map); |
| } |
| |
| static struct resv_map *vma_resv_map(struct vm_area_struct *vma) |
| { |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| if (!(vma->vm_flags & VM_SHARED)) |
| return (struct resv_map *)(get_vma_private_data(vma) & |
| ~HPAGE_RESV_MASK); |
| return NULL; |
| } |
| |
| static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) |
| { |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| VM_BUG_ON(vma->vm_flags & VM_SHARED); |
| |
| 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_SHARED); |
| |
| set_vma_private_data(vma, get_vma_private_data(vma) | flags); |
| } |
| |
| static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) |
| { |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| |
| return (get_vma_private_data(vma) & flag) != 0; |
| } |
| |
| /* Decrement the reserved pages in the hugepage pool by one */ |
| static void decrement_hugepage_resv_vma(struct hstate *h, |
| struct vm_area_struct *vma) |
| { |
| if (vma->vm_flags & VM_NORESERVE) |
| return; |
| |
| if (vma->vm_flags & VM_SHARED) { |
| /* Shared mappings always use reserves */ |
| h->resv_huge_pages--; |
| } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| /* |
| * Only the process that called mmap() has reserves for |
| * private mappings. |
| */ |
| h->resv_huge_pages--; |
| } |
| } |
| |
| /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ |
| void reset_vma_resv_huge_pages(struct vm_area_struct *vma) |
| { |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| if (!(vma->vm_flags & VM_SHARED)) |
| vma->vm_private_data = (void *)0; |
| } |
| |
| /* Returns true if the VMA has associated reserve pages */ |
| static int vma_has_reserves(struct vm_area_struct *vma) |
| { |
| if (vma->vm_flags & VM_SHARED) |
| return 1; |
| if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
| return 1; |
| return 0; |
| } |
| |
| static void clear_gigantic_page(struct page *page, |
| unsigned long addr, unsigned long sz) |
| { |
| int i; |
| struct page *p = page; |
| |
| might_sleep(); |
| for (i = 0; i < sz/PAGE_SIZE; i++, p = mem_map_next(p, page, i)) { |
| cond_resched(); |
| clear_user_highpage(p, addr + i * PAGE_SIZE); |
| } |
| } |
| static void clear_huge_page(struct page *page, |
| unsigned long addr, unsigned long sz) |
| { |
| int i; |
| |
| if (unlikely(sz > MAX_ORDER_NR_PAGES)) { |
| clear_gigantic_page(page, addr, sz); |
| return; |
| } |
| |
| might_sleep(); |
| for (i = 0; i < sz/PAGE_SIZE; i++) { |
| cond_resched(); |
| clear_user_highpage(page + i, addr + i * PAGE_SIZE); |
| } |
| } |
| |
| static void copy_gigantic_page(struct page *dst, struct page *src, |
| unsigned long addr, struct vm_area_struct *vma) |
| { |
| int i; |
| struct hstate *h = hstate_vma(vma); |
| struct page *dst_base = dst; |
| struct page *src_base = src; |
| might_sleep(); |
| for (i = 0; i < pages_per_huge_page(h); ) { |
| cond_resched(); |
| copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); |
| |
| i++; |
| dst = mem_map_next(dst, dst_base, i); |
| src = mem_map_next(src, src_base, i); |
| } |
| } |
| static void copy_huge_page(struct page *dst, struct page *src, |
| unsigned long addr, struct vm_area_struct *vma) |
| { |
| int i; |
| struct hstate *h = hstate_vma(vma); |
| |
| if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) { |
| copy_gigantic_page(dst, src, addr, vma); |
| return; |
| } |
| |
| might_sleep(); |
| for (i = 0; i < pages_per_huge_page(h); i++) { |
| cond_resched(); |
| copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); |
| } |
| } |
| |
| static void enqueue_huge_page(struct hstate *h, struct page *page) |
| { |
| int nid = page_to_nid(page); |
| list_add(&page->lru, &h->hugepage_freelists[nid]); |
| h->free_huge_pages++; |
| h->free_huge_pages_node[nid]++; |
| } |
| |
| static struct page *dequeue_huge_page(struct hstate *h) |
| { |
| int nid; |
| struct page *page = NULL; |
| |
| for (nid = 0; nid < MAX_NUMNODES; ++nid) { |
| if (!list_empty(&h->hugepage_freelists[nid])) { |
| page = list_entry(h->hugepage_freelists[nid].next, |
| struct page, lru); |
| list_del(&page->lru); |
| h->free_huge_pages--; |
| h->free_huge_pages_node[nid]--; |
| break; |
| } |
| } |
| return page; |
| } |
| |
| static struct page *dequeue_huge_page_vma(struct hstate *h, |
| struct vm_area_struct *vma, |
| unsigned long address, int avoid_reserve) |
| { |
| int nid; |
| struct page *page = NULL; |
| struct mempolicy *mpol; |
| nodemask_t *nodemask; |
| struct zonelist *zonelist = huge_zonelist(vma, address, |
| htlb_alloc_mask, &mpol, &nodemask); |
| struct zone *zone; |
| struct zoneref *z; |
| |
| /* |
| * A child process with MAP_PRIVATE mappings created by their parent |
| * have no page reserves. This check ensures that reservations are |
| * not "stolen". The child may still get SIGKILLed |
| */ |
| if (!vma_has_reserves(vma) && |
| h->free_huge_pages - h->resv_huge_pages == 0) |
| return NULL; |
| |
| /* If reserves cannot be used, ensure enough pages are in the pool */ |
| if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) |
| return NULL; |
| |
| for_each_zone_zonelist_nodemask(zone, z, zonelist, |
| MAX_NR_ZONES - 1, nodemask) { |
| nid = zone_to_nid(zone); |
| if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) && |
| !list_empty(&h->hugepage_freelists[nid])) { |
| page = list_entry(h->hugepage_freelists[nid].next, |
| struct page, lru); |
| list_del(&page->lru); |
| h->free_huge_pages--; |
| h->free_huge_pages_node[nid]--; |
| |
| if (!avoid_reserve) |
| decrement_hugepage_resv_vma(h, vma); |
| |
| break; |
| } |
| } |
| mpol_cond_put(mpol); |
| return page; |
| } |
| |
| static void update_and_free_page(struct hstate *h, struct page *page) |
| { |
| int i; |
| |
| VM_BUG_ON(h->order >= MAX_ORDER); |
| |
| h->nr_huge_pages--; |
| h->nr_huge_pages_node[page_to_nid(page)]--; |
| for (i = 0; i < pages_per_huge_page(h); i++) { |
| page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | |
| 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | |
| 1 << PG_private | 1<< PG_writeback); |
| } |
| set_compound_page_dtor(page, NULL); |
| set_page_refcounted(page); |
| arch_release_hugepage(page); |
| __free_pages(page, huge_page_order(h)); |
| } |
| |
| struct hstate *size_to_hstate(unsigned long size) |
| { |
| struct hstate *h; |
| |
| for_each_hstate(h) { |
| if (huge_page_size(h) == size) |
| return h; |
| } |
| return NULL; |
| } |
| |
| static void free_huge_page(struct page *page) |
| { |
| /* |
| * Can't pass hstate in here because it is called from the |
| * compound page destructor. |
| */ |
| struct hstate *h = page_hstate(page); |
| int nid = page_to_nid(page); |
| struct address_space *mapping; |
| |
| mapping = (struct address_space *) page_private(page); |
| set_page_private(page, 0); |
| BUG_ON(page_count(page)); |
| INIT_LIST_HEAD(&page->lru); |
| |
| spin_lock(&hugetlb_lock); |
| if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { |
| update_and_free_page(h, page); |
| h->surplus_huge_pages--; |
| h->surplus_huge_pages_node[nid]--; |
| } else { |
| enqueue_huge_page(h, page); |
| } |
| spin_unlock(&hugetlb_lock); |
| if (mapping) |
| hugetlb_put_quota(mapping, 1); |
| } |
| |
| /* |
| * 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, int delta) |
| { |
| static int prev_nid; |
| int nid = prev_nid; |
| int ret = 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); |
| |
| /* To shrink on this node, there must be a surplus page */ |
| if (delta < 0 && !h->surplus_huge_pages_node[nid]) |
| continue; |
| /* Surplus cannot exceed the total number of pages */ |
| if (delta > 0 && h->surplus_huge_pages_node[nid] >= |
| h->nr_huge_pages_node[nid]) |
| continue; |
| |
| h->surplus_huge_pages += delta; |
| h->surplus_huge_pages_node[nid] += delta; |
| ret = 1; |
| break; |
| } while (nid != prev_nid); |
| |
| prev_nid = nid; |
| return ret; |
| } |
| |
| static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) |
| { |
| set_compound_page_dtor(page, free_huge_page); |
| spin_lock(&hugetlb_lock); |
| h->nr_huge_pages++; |
| h->nr_huge_pages_node[nid]++; |
| spin_unlock(&hugetlb_lock); |
| put_page(page); /* free it into the hugepage allocator */ |
| } |
| |
| static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) |
| { |
| struct page *page; |
| |
| if (h->order >= MAX_ORDER) |
| return NULL; |
| |
| page = alloc_pages_node(nid, |
| htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| |
| __GFP_REPEAT|__GFP_NOWARN, |
| huge_page_order(h)); |
| if (page) { |
| if (arch_prepare_hugepage(page)) { |
| __free_pages(page, huge_page_order(h)); |
| return NULL; |
| } |
| prep_new_huge_page(h, page, nid); |
| } |
| |
| return page; |
| } |
| |
| /* |
| * 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. |
| */ |
| static int hstate_next_node(struct hstate *h) |
| { |
| int next_nid; |
| next_nid = next_node(h->hugetlb_next_nid, node_online_map); |
| if (next_nid == MAX_NUMNODES) |
| next_nid = first_node(node_online_map); |
| h->hugetlb_next_nid = next_nid; |
| return next_nid; |
| } |
| |
| static int alloc_fresh_huge_page(struct hstate *h) |
| { |
| struct page *page; |
| int start_nid; |
| int next_nid; |
| int ret = 0; |
| |
| start_nid = h->hugetlb_next_nid; |
| |
| do { |
| page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid); |
| if (page) |
| ret = 1; |
| next_nid = hstate_next_node(h); |
| } while (!page && h->hugetlb_next_nid != start_nid); |
| |
| if (ret) |
| count_vm_event(HTLB_BUDDY_PGALLOC); |
| else |
| count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| |
| return ret; |
| } |
| |
| static struct page *alloc_buddy_huge_page(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long address) |
| { |
| struct page *page; |
| unsigned int nid; |
| |
| if (h->order >= MAX_ORDER) |
| return NULL; |
| |
| /* |
| * Assume we will successfully allocate the surplus page to |
| * prevent racing processes from causing the surplus to exceed |
| * overcommit |
| * |
| * This however introduces a different race, where a process B |
| * tries to grow the static hugepage pool while alloc_pages() is |
| * called by process A. B will only examine the per-node |
| * counters in determining if surplus huge pages can be |
| * converted to normal huge pages in adjust_pool_surplus(). A |
| * won't be able to increment the per-node counter, until the |
| * lock is dropped by B, but B doesn't drop hugetlb_lock until |
| * no more huge pages can be converted from surplus to normal |
| * state (and doesn't try to convert again). Thus, we have a |
| * case where a surplus huge page exists, the pool is grown, and |
| * the surplus huge page still exists after, even though it |
| * should just have been converted to a normal huge page. This |
| * does not leak memory, though, as the hugepage will be freed |
| * once it is out of use. It also does not allow the counters to |
| * go out of whack in adjust_pool_surplus() as we don't modify |
| * the node values until we've gotten the hugepage and only the |
| * per-node value is checked there. |
| */ |
| spin_lock(&hugetlb_lock); |
| if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { |
| spin_unlock(&hugetlb_lock); |
| return NULL; |
| } else { |
| h->nr_huge_pages++; |
| h->surplus_huge_pages++; |
| } |
| spin_unlock(&hugetlb_lock); |
| |
| page = alloc_pages(htlb_alloc_mask|__GFP_COMP| |
| __GFP_REPEAT|__GFP_NOWARN, |
| huge_page_order(h)); |
| |
| if (page && arch_prepare_hugepage(page)) { |
| __free_pages(page, huge_page_order(h)); |
| return NULL; |
| } |
| |
| spin_lock(&hugetlb_lock); |
| if (page) { |
| /* |
| * 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); |
| set_compound_page_dtor(page, free_huge_page); |
| /* |
| * We incremented the global counters already |
| */ |
| h->nr_huge_pages_node[nid]++; |
| h->surplus_huge_pages_node[nid]++; |
| __count_vm_event(HTLB_BUDDY_PGALLOC); |
| } else { |
| h->nr_huge_pages--; |
| h->surplus_huge_pages--; |
| __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| } |
| spin_unlock(&hugetlb_lock); |
| |
| return page; |
| } |
| |
| /* |
| * Increase the hugetlb pool such that it can accomodate a reservation |
| * of size 'delta'. |
| */ |
| static int gather_surplus_pages(struct hstate *h, int delta) |
| { |
| struct list_head surplus_list; |
| struct page *page, *tmp; |
| int ret, i; |
| int needed, allocated; |
| |
| needed = (h->resv_huge_pages + delta) - h->free_huge_pages; |
| if (needed <= 0) { |
| h->resv_huge_pages += delta; |
| return 0; |
| } |
| |
| allocated = 0; |
| INIT_LIST_HEAD(&surplus_list); |
| |
| ret = -ENOMEM; |
| retry: |
| spin_unlock(&hugetlb_lock); |
| for (i = 0; i < needed; i++) { |
| page = alloc_buddy_huge_page(h, NULL, 0); |
| 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; |
| } |
| |
| list_add(&page->lru, &surplus_list); |
| } |
| allocated += needed; |
| |
| /* |
| * After retaking hugetlb_lock, we need to recalculate 'needed' |
| * because either resv_huge_pages or free_huge_pages may have changed. |
| */ |
| spin_lock(&hugetlb_lock); |
| needed = (h->resv_huge_pages + delta) - |
| (h->free_huge_pages + allocated); |
| if (needed > 0) |
| goto retry; |
| |
| /* |
| * The surplus_list now contains _at_least_ the number of extra pages |
| * needed to accomodate the reservation. Add the appropriate number |
| * of pages to the hugetlb pool and free the extras back to the buddy |
| * allocator. Commit the entire reservation here to prevent another |
| * process from stealing the pages as they are added to the pool but |
| * before they are reserved. |
| */ |
| needed += allocated; |
| h->resv_huge_pages += delta; |
| ret = 0; |
| free: |
| /* Free the needed pages to the hugetlb pool */ |
| list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
| if ((--needed) < 0) |
| break; |
| list_del(&page->lru); |
| enqueue_huge_page(h, page); |
| } |
| |
| /* Free unnecessary surplus pages to the buddy allocator */ |
| if (!list_empty(&surplus_list)) { |
| spin_unlock(&hugetlb_lock); |
| list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
| list_del(&page->lru); |
| /* |
| * 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. |
| */ |
| free_huge_page(page); |
| } |
| spin_lock(&hugetlb_lock); |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * When releasing a hugetlb pool reservation, any surplus pages that were |
| * allocated to satisfy the reservation must be explicitly freed if they were |
| * never used. |
| */ |
| 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; |
| |
| /* |
| * 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. |
| */ |
| unsigned long remaining_iterations = num_online_nodes(); |
| |
| /* Uncommit the reservation */ |
| h->resv_huge_pages -= unused_resv_pages; |
| |
| /* Cannot return gigantic pages currently */ |
| if (h->order >= MAX_ORDER) |
| return; |
| |
| nr_pages = min(unused_resv_pages, h->surplus_huge_pages); |
| |
| while (remaining_iterations-- && nr_pages) { |
| nid = next_node(nid, node_online_map); |
| if (nid == MAX_NUMNODES) |
| nid = first_node(node_online_map); |
| |
| if (!h->surplus_huge_pages_node[nid]) |
| continue; |
| |
| if (!list_empty(&h->hugepage_freelists[nid])) { |
| page = list_entry(h->hugepage_freelists[nid].next, |
| struct page, lru); |
| list_del(&page->lru); |
| update_and_free_page(h, page); |
| h->free_huge_pages--; |
| h->free_huge_pages_node[nid]--; |
| h->surplus_huge_pages--; |
| h->surplus_huge_pages_node[nid]--; |
| nr_pages--; |
| remaining_iterations = num_online_nodes(); |
| } |
| } |
| } |
| |
| /* |
| * Determine if the huge page at addr within the vma has an associated |
| * reservation. Where it does not we will need to logically increase |
| * reservation and actually increase quota before an allocation can occur. |
| * Where any new reservation would be required the reservation change is |
| * prepared, but not committed. Once the page has been quota'd allocated |
| * an instantiated the change should be committed via vma_commit_reservation. |
| * No action is required on failure. |
| */ |
| static int vma_needs_reservation(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr) |
| { |
| struct address_space *mapping = vma->vm_file->f_mapping; |
| struct inode *inode = mapping->host; |
| |
| if (vma->vm_flags & VM_SHARED) { |
| pgoff_t idx = vma_hugecache_offset(h, vma, addr); |
| return region_chg(&inode->i_mapping->private_list, |
| idx, idx + 1); |
| |
| } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| return 1; |
| |
| } else { |
| int err; |
| pgoff_t idx = vma_hugecache_offset(h, vma, addr); |
| struct resv_map *reservations = vma_resv_map(vma); |
| |
| err = region_chg(&reservations->regions, idx, idx + 1); |
| if (err < 0) |
| return err; |
| return 0; |
| } |
| } |
| static void vma_commit_reservation(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long addr) |
| { |
| struct address_space *mapping = vma->vm_file->f_mapping; |
| struct inode *inode = mapping->host; |
| |
| if (vma->vm_flags & VM_SHARED) { |
| pgoff_t idx = vma_hugecache_offset(h, vma, addr); |
| region_add(&inode->i_mapping->private_list, idx, idx + 1); |
| |
| } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| pgoff_t idx = vma_hugecache_offset(h, vma, addr); |
| struct resv_map *reservations = vma_resv_map(vma); |
| |
| /* Mark this page used in the map. */ |
| region_add(&reservations->regions, idx, idx + 1); |
| } |
| } |
| |
| static struct page *alloc_huge_page(struct vm_area_struct *vma, |
| unsigned long addr, int avoid_reserve) |
| { |
| struct hstate *h = hstate_vma(vma); |
| struct page *page; |
| struct address_space *mapping = vma->vm_file->f_mapping; |
| struct inode *inode = mapping->host; |
| unsigned int chg; |
| |
| /* |
| * Processes that did not create the mapping will have no reserves and |
| * will not have accounted against quota. Check that the quota can be |
| * made before satisfying the allocation |
| * MAP_NORESERVE mappings may also need pages and quota allocated |
| * if no reserve mapping overlaps. |
| */ |
| chg = vma_needs_reservation(h, vma, addr); |
| if (chg < 0) |
| return ERR_PTR(chg); |
| if (chg) |
| if (hugetlb_get_quota(inode->i_mapping, chg)) |
| return ERR_PTR(-ENOSPC); |
| |
| spin_lock(&hugetlb_lock); |
| page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); |
| spin_unlock(&hugetlb_lock); |
| |
| if (!page) { |
| page = alloc_buddy_huge_page(h, vma, addr); |
| if (!page) { |
| hugetlb_put_quota(inode->i_mapping, chg); |
| return ERR_PTR(-VM_FAULT_OOM); |
| } |
| } |
| |
| set_page_refcounted(page); |
| set_page_private(page, (unsigned long) mapping); |
| |
| vma_commit_reservation(h, vma, addr); |
| |
| return page; |
| } |
| |
| int __weak alloc_bootmem_huge_page(struct hstate *h) |
| { |
| struct huge_bootmem_page *m; |
| int nr_nodes = nodes_weight(node_online_map); |
| |
| while (nr_nodes) { |
| void *addr; |
| |
| addr = __alloc_bootmem_node_nopanic( |
| NODE_DATA(h->hugetlb_next_nid), |
| huge_page_size(h), huge_page_size(h), 0); |
| |
| if (addr) { |
| /* |
| * Use the beginning of the huge page to store the |
| * huge_bootmem_page struct (until gather_bootmem |
| * puts them into the mem_map). |
| */ |
| m = addr; |
| goto found; |
| } |
| hstate_next_node(h); |
| nr_nodes--; |
| } |
| return 0; |
| |
| found: |
| BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1)); |
| /* Put them into a private list first because mem_map is not up yet */ |
| list_add(&m->list, &huge_boot_pages); |
| m->hstate = h; |
| return 1; |
| } |
| |
| static void prep_compound_huge_page(struct page *page, int order) |
| { |
| if (unlikely(order > (MAX_ORDER - 1))) |
| prep_compound_gigantic_page(page, order); |
| else |
| prep_compound_page(page, order); |
| } |
| |
| /* Put bootmem huge pages into the standard lists after mem_map is up */ |
| static void __init gather_bootmem_prealloc(void) |
| { |
| struct huge_bootmem_page *m; |
| |
| list_for_each_entry(m, &huge_boot_pages, list) { |
| struct page *page = virt_to_page(m); |
| struct hstate *h = m->hstate; |
| __ClearPageReserved(page); |
| WARN_ON(page_count(page) != 1); |
| prep_compound_huge_page(page, h->order); |
| prep_new_huge_page(h, page, page_to_nid(page)); |
| } |
| } |
| |
| static void __init hugetlb_hstate_alloc_pages(struct hstate *h) |
| { |
| unsigned long i; |
| |
| for (i = 0; i < h->max_huge_pages; ++i) { |
| if (h->order >= MAX_ORDER) { |
| if (!alloc_bootmem_huge_page(h)) |
| break; |
| } else if (!alloc_fresh_huge_page(h)) |
| break; |
| } |
| h->max_huge_pages = i; |
| } |
| |
| static void __init hugetlb_init_hstates(void) |
| { |
| struct hstate *h; |
| |
| for_each_hstate(h) { |
| /* oversize hugepages were init'ed in early boot */ |
| if (h->order < MAX_ORDER) |
| hugetlb_hstate_alloc_pages(h); |
| } |
| } |
| |
| static char * __init memfmt(char *buf, unsigned long n) |
| { |
| if (n >= (1UL << 30)) |
| sprintf(buf, "%lu GB", n >> 30); |
| else if (n >= (1UL << 20)) |
| sprintf(buf, "%lu MB", n >> 20); |
| else |
| sprintf(buf, "%lu KB", n >> 10); |
| return buf; |
| } |
| |
| static void __init report_hugepages(void) |
| { |
| struct hstate *h; |
| |
| for_each_hstate(h) { |
| char buf[32]; |
| printk(KERN_INFO "HugeTLB registered %s page size, " |
| "pre-allocated %ld pages\n", |
| memfmt(buf, huge_page_size(h)), |
| h->free_huge_pages); |
| } |
| } |
| |
| #ifdef CONFIG_HIGHMEM |
| static void try_to_free_low(struct hstate *h, unsigned long count) |
| { |
| int i; |
| |
| if (h->order >= MAX_ORDER) |
| return; |
| |
| for (i = 0; i < MAX_NUMNODES; ++i) { |
| struct page *page, *next; |
| struct list_head *freel = &h->hugepage_freelists[i]; |
| list_for_each_entry_safe(page, next, freel, lru) { |
| if (count >= h->nr_huge_pages) |
| return; |
| if (PageHighMem(page)) |
| continue; |
| list_del(&page->lru); |
| update_and_free_page(h, page); |
| h->free_huge_pages--; |
| h->free_huge_pages_node[page_to_nid(page)]--; |
| } |
| } |
| } |
| #else |
| static inline void try_to_free_low(struct hstate *h, unsigned long count) |
| { |
| } |
| #endif |
| |
| #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) |
| { |
| unsigned long min_count, ret; |
| |
| if (h->order >= MAX_ORDER) |
| return h->max_huge_pages; |
| |
| /* |
| * Increase the pool size |
| * First take pages out of surplus state. Then make up the |
| * remaining difference by allocating fresh huge pages. |
| * |
| * We might race with alloc_buddy_huge_page() here and be unable |
| * to convert a surplus huge page to a normal huge page. That is |
| * not critical, though, it just means the overall size of the |
| * pool might be one hugepage larger than it needs to be, but |
| * within all the constraints specified by the sysctls. |
| */ |
| spin_lock(&hugetlb_lock); |
| while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { |
| if (!adjust_pool_surplus(h, -1)) |
| break; |
| } |
| |
| while (count > persistent_huge_pages(h)) { |
| /* |
| * If this allocation races such that we no longer need the |
| * page, free_huge_page will handle it by freeing the page |
| * and reducing the surplus. |
| */ |
| spin_unlock(&hugetlb_lock); |
| ret = alloc_fresh_huge_page(h); |
| spin_lock(&hugetlb_lock); |
| if (!ret) |
| goto out; |
| |
| } |
| |
| /* |
| * Decrease the pool size |
| * First return free pages to the buddy allocator (being careful |
| * to keep enough around to satisfy reservations). Then place |
| * pages into surplus state as needed so the pool will shrink |
| * to the desired size as pages become free. |
| * |
| * By placing pages into the surplus state independent of the |
| * overcommit value, we are allowing the surplus pool size to |
| * exceed overcommit. There are few sane options here. Since |
| * alloc_buddy_huge_page() is checking the global counter, |
| * though, we'll note that we're not allowed to exceed surplus |
| * and won't grow the pool anywhere else. Not until one of the |
| * sysctls are changed, or the surplus pages go out of use. |
| */ |
| min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; |
| min_count = max(count, min_count); |
| try_to_free_low(h, min_count); |
| while (min_count < persistent_huge_pages(h)) { |
| struct page *page = dequeue_huge_page(h); |
| if (!page) |
| break; |
| update_and_free_page(h, page); |
| } |
| while (count < persistent_huge_pages(h)) { |
| if (!adjust_pool_surplus(h, 1)) |
| break; |
| } |
| out: |
| ret = persistent_huge_pages(h); |
| spin_unlock(&hugetlb_lock); |
| return ret; |
| } |
| |
| #define HSTATE_ATTR_RO(_name) \ |
| static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
| |
| #define HSTATE_ATTR(_name) \ |
| static struct kobj_attribute _name##_attr = \ |
| __ATTR(_name, 0644, _name##_show, _name##_store) |
| |
| static struct kobject *hugepages_kobj; |
| static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
| |
| static struct hstate *kobj_to_hstate(struct kobject *kobj) |
| { |
| int i; |
| for (i = 0; i < HUGE_MAX_HSTATE; i++) |
| if (hstate_kobjs[i] == kobj) |
| return &hstates[i]; |
| BUG(); |
| return NULL; |
| } |
| |
| static ssize_t nr_hugepages_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| struct hstate *h = kobj_to_hstate(kobj); |
| return sprintf(buf, "%lu\n", h->nr_huge_pages); |
| } |
| static ssize_t nr_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); |
| |
| err = strict_strtoul(buf, 10, &input); |
| if (err) |
| return 0; |
| |
| h->max_huge_pages = set_max_huge_pages(h, input); |
| |
| return count; |
| } |
| HSTATE_ATTR(nr_hugepages); |
| |
| static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| struct hstate *h = kobj_to_hstate(kobj); |
| 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); |
| |
| err = strict_strtoul(buf, 10, &input); |
| if (err) |
| return 0; |
| |
| spin_lock(&hugetlb_lock); |
| h->nr_overcommit_huge_pages = input; |
| spin_unlock(&hugetlb_lock); |
| |
| return count; |
| } |
| HSTATE_ATTR(nr_overcommit_hugepages); |
| |
| static ssize_t free_hugepages_show(struct kobject *kobj, |
| struct kobj_attribute *attr, char *buf) |
| { |
| struct hstate *h = kobj_to_hstate(kobj); |
| return sprintf(buf, "%lu\n", h->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); |
| 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 = kobj_to_hstate(kobj); |
| return sprintf(buf, "%lu\n", h->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, |
| NULL, |
| }; |
| |
| static struct attribute_group hstate_attr_group = { |
| .attrs = hstate_attrs, |
| }; |
| |
| static int __init hugetlb_sysfs_add_hstate(struct hstate *h) |
| { |
| int retval; |
| |
| hstate_kobjs[h - hstates] = kobject_create_and_add(h->name, |
| hugepages_kobj); |
| if (!hstate_kobjs[h - hstates]) |
| return -ENOMEM; |
| |
| retval = sysfs_create_group(hstate_kobjs[h - hstates], |
| &hstate_attr_group); |
| if (retval) |
| kobject_put(hstate_kobjs[h - hstates]); |
| |
| 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); |
| if (err) |
| printk(KERN_ERR "Hugetlb: Unable to add hstate %s", |
| h->name); |
| } |
| } |
| |
| static void __exit hugetlb_exit(void) |
| { |
| struct hstate *h; |
| |
| for_each_hstate(h) { |
| kobject_put(hstate_kobjs[h - hstates]); |
| } |
| |
| kobject_put(hugepages_kobj); |
| } |
| module_exit(hugetlb_exit); |
| |
| static int __init hugetlb_init(void) |
| { |
| /* Some platform decide whether they support huge pages at boot |
| * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when |
| * there is no such support |
| */ |
| if (HPAGE_SHIFT == 0) |
| return 0; |
| |
| if (!size_to_hstate(default_hstate_size)) { |
| default_hstate_size = HPAGE_SIZE; |
| if (!size_to_hstate(default_hstate_size)) |
| hugetlb_add_hstate(HUGETLB_PAGE_ORDER); |
| } |
| default_hstate_idx = size_to_hstate(default_hstate_size) - hstates; |
| if (default_hstate_max_huge_pages) |
| default_hstate.max_huge_pages = default_hstate_max_huge_pages; |
| |
| hugetlb_init_hstates(); |
| |
| gather_bootmem_prealloc(); |
| |
| report_hugepages(); |
| |
| hugetlb_sysfs_init(); |
| |
| return 0; |
| } |
| module_init(hugetlb_init); |
| |
| /* Should be called on processing a hugepagesz=... option */ |
| void __init hugetlb_add_hstate(unsigned order) |
| { |
| struct hstate *h; |
| unsigned long i; |
| |
| if (size_to_hstate(PAGE_SIZE << order)) { |
| printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); |
| return; |
| } |
| BUG_ON(max_hstate >= HUGE_MAX_HSTATE); |
| BUG_ON(order == 0); |
| h = &hstates[max_hstate++]; |
| h->order = order; |
| h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); |
| h->nr_huge_pages = 0; |
| h->free_huge_pages = 0; |
| for (i = 0; i < MAX_NUMNODES; ++i) |
| INIT_LIST_HEAD(&h->hugepage_freelists[i]); |
| h->hugetlb_next_nid = first_node(node_online_map); |
| snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", |
| huge_page_size(h)/1024); |
| |
| parsed_hstate = h; |
| } |
| |
| static int __init hugetlb_nrpages_setup(char *s) |
| { |
| unsigned long *mhp; |
| static unsigned long *last_mhp; |
| |
| /* |
| * !max_hstate means we haven't parsed a hugepagesz= parameter yet, |
| * so this hugepages= parameter goes to the "default hstate". |
| */ |
| if (!max_hstate) |
| mhp = &default_hstate_max_huge_pages; |
| else |
| mhp = &parsed_hstate->max_huge_pages; |
| |
| if (mhp == last_mhp) { |
| printk(KERN_WARNING "hugepages= specified twice without " |
| "interleaving hugepagesz=, ignoring\n"); |
| return 1; |
| } |
| |
| if (sscanf(s, "%lu", mhp) <= 0) |
| *mhp = 0; |
| |
| /* |
| * Global state is always initialized later in hugetlb_init. |
| * But we need to allocate >= MAX_ORDER hstates here early to still |
| * use the bootmem allocator. |
| */ |
| if (max_hstate && parsed_hstate->order >= MAX_ORDER) |
| hugetlb_hstate_alloc_pages(parsed_hstate); |
| |
| last_mhp = mhp; |
| |
| return 1; |
| } |
| __setup("hugepages=", hugetlb_nrpages_setup); |
| |
| static int __init hugetlb_default_setup(char *s) |
| { |
| default_hstate_size = memparse(s, &s); |
| return 1; |
| } |
| __setup("default_hugepagesz=", hugetlb_default_setup); |
| |
| static unsigned int cpuset_mems_nr(unsigned int *array) |
| { |
| int node; |
| unsigned int nr = 0; |
| |
| for_each_node_mask(node, cpuset_current_mems_allowed) |
| nr += array[node]; |
| |
| return nr; |
| } |
| |
| #ifdef CONFIG_SYSCTL |
| int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
| struct file *file, void __user *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| struct hstate *h = &default_hstate; |
| unsigned long tmp; |
| |
| if (!write) |
| tmp = h->max_huge_pages; |
| |
| table->data = &tmp; |
| table->maxlen = sizeof(unsigned long); |
| proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
| |
| if (write) |
| h->max_huge_pages = set_max_huge_pages(h, tmp); |
| |
| return 0; |
| } |
| |
| int hugetlb_treat_movable_handler(struct ctl_table *table, int write, |
| struct file *file, void __user *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| proc_dointvec(table, write, file, buffer, length, ppos); |
| if (hugepages_treat_as_movable) |
| htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; |
| else |
| htlb_alloc_mask = GFP_HIGHUSER; |
| return 0; |
| } |
| |
| int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
| struct file *file, void __user *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| struct hstate *h = &default_hstate; |
| unsigned long tmp; |
| |
| if (!write) |
| tmp = h->nr_overcommit_huge_pages; |
| |
| table->data = &tmp; |
| table->maxlen = sizeof(unsigned long); |
| proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
| |
| if (write) { |
| spin_lock(&hugetlb_lock); |
| h->nr_overcommit_huge_pages = tmp; |
| spin_unlock(&hugetlb_lock); |
| } |
| |
| return 0; |
| } |
| |
| #endif /* CONFIG_SYSCTL */ |
| |
| void hugetlb_report_meminfo(struct seq_file *m) |
| { |
| struct hstate *h = &default_hstate; |
| seq_printf(m, |
| "HugePages_Total: %5lu\n" |
| "HugePages_Free: %5lu\n" |
| "HugePages_Rsvd: %5lu\n" |
| "HugePages_Surp: %5lu\n" |
| "Hugepagesize: %8lu kB\n", |
| h->nr_huge_pages, |
| h->free_huge_pages, |
| h->resv_huge_pages, |
| h->surplus_huge_pages, |
| 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
| } |
| |
| int hugetlb_report_node_meminfo(int nid, char *buf) |
| { |
| struct hstate *h = &default_hstate; |
| return sprintf(buf, |
| "Node %d HugePages_Total: %5u\n" |
| "Node %d HugePages_Free: %5u\n" |
| "Node %d HugePages_Surp: %5u\n", |
| nid, h->nr_huge_pages_node[nid], |
| nid, h->free_huge_pages_node[nid], |
| nid, h->surplus_huge_pages_node[nid]); |
| } |
| |
| /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
| unsigned long hugetlb_total_pages(void) |
| { |
| struct hstate *h = &default_hstate; |
| return h->nr_huge_pages * pages_per_huge_page(h); |
| } |
| |
| static int hugetlb_acct_memory(struct hstate *h, long delta) |
| { |
| int ret = -ENOMEM; |
| |
| spin_lock(&hugetlb_lock); |
| /* |
| * When cpuset is configured, it breaks the strict hugetlb page |
| * reservation as the accounting is done on a global variable. Such |
| * reservation is completely rubbish in the presence of cpuset because |
| * the reservation is not checked against page availability for the |
| * current cpuset. Application can still potentially OOM'ed by kernel |
| * with lack of free htlb page in cpuset that the task is in. |
| * Attempt to enforce strict accounting with cpuset is almost |
| * impossible (or too ugly) because cpuset is too fluid that |
| * task or memory node can be dynamically moved between cpusets. |
| * |
| * The change of semantics for shared hugetlb mapping with cpuset is |
| * undesirable. However, in order to preserve some of the semantics, |
| * we fall back to check against current free page availability as |
| * a best attempt and hopefully to minimize the impact of changing |
| * semantics that cpuset has. |
| */ |
| if (delta > 0) { |
| if (gather_surplus_pages(h, delta) < 0) |
| goto out; |
| |
| if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { |
| return_unused_surplus_pages(h, delta); |
| goto out; |
| } |
| } |
| |
| ret = 0; |
| if (delta < 0) |
| return_unused_surplus_pages(h, (unsigned long) -delta); |
| |
| out: |
| spin_unlock(&hugetlb_lock); |
| return ret; |
| } |
| |
| static void hugetlb_vm_op_open(struct vm_area_struct *vma) |
| { |
| struct resv_map *reservations = vma_resv_map(vma); |
| |
| /* |
| * This new VMA should share its siblings reservation map if present. |
| * The VMA will only ever have a valid reservation map pointer where |
| * it is being copied for another still existing VMA. As that VMA |
| * has a reference to the reservation map it cannot dissappear until |
| * after this open call completes. It is therefore safe to take a |
| * new reference here without additional locking. |
| */ |
| if (reservations) |
| kref_get(&reservations->refs); |
| } |
| |
| static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
| { |
| struct hstate *h = hstate_vma(vma); |
| struct resv_map *reservations = vma_resv_map(vma); |
| unsigned long reserve; |
| unsigned long start; |
| unsigned long end; |
| |
| if (reservations) { |
| start = vma_hugecache_offset(h, vma, vma->vm_start); |
| end = vma_hugecache_offset(h, vma, vma->vm_end); |
| |
| reserve = (end - start) - |
| region_count(&reservations->regions, start, end); |
| |
| kref_put(&reservations->refs, resv_map_release); |
| |
| if (reserve) { |
| hugetlb_acct_memory(h, -reserve); |
| hugetlb_put_quota(vma->vm_file->f_mapping, reserve); |
| } |
| } |
| } |
| |
| /* |
| * We cannot handle pagefaults against hugetlb pages at all. They cause |
| * handle_mm_fault() to try to instantiate regular-sized pages in the |
| * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
| * this far. |
| */ |
| static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| { |
| BUG(); |
| return 0; |
| } |
| |
| struct vm_operations_struct hugetlb_vm_ops = { |
| .fault = hugetlb_vm_op_fault, |
| .open = hugetlb_vm_op_open, |
| .close = hugetlb_vm_op_close, |
| }; |
| |
| static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
| int writable) |
| { |
| pte_t entry; |
| |
| if (writable) { |
| entry = |
| pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); |
| } else { |
| entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); |
| } |
| entry = pte_mkyoung(entry); |
| entry = pte_mkhuge(entry); |
| |
| return entry; |
| } |
| |
| static void set_huge_ptep_writable(struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep) |
| { |
| pte_t entry; |
| |
| entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); |
| if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { |
| update_mmu_cache(vma, address, entry); |
| } |
| } |
| |
| |
| int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
| struct vm_area_struct *vma) |
| { |
| pte_t *src_pte, *dst_pte, entry; |
| struct page *ptepage; |
| unsigned long addr; |
| int cow; |
| struct hstate *h = hstate_vma(vma); |
| unsigned long sz = huge_page_size(h); |
| |
| cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
| |
| for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { |
| src_pte = huge_pte_offset(src, addr); |
| if (!src_pte) |
| continue; |
| dst_pte = huge_pte_alloc(dst, addr, sz); |
| if (!dst_pte) |
| goto nomem; |
| |
| /* If the pagetables are shared don't copy or take references */ |
| if (dst_pte == src_pte) |
| continue; |
| |
| spin_lock(&dst->page_table_lock); |
| spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); |
| if (!huge_pte_none(huge_ptep_get(src_pte))) { |
| if (cow) |
| huge_ptep_set_wrprotect(src, addr, src_pte); |
| entry = huge_ptep_get(src_pte); |
| ptepage = pte_page(entry); |
| get_page(ptepage); |
| set_huge_pte_at(dst, addr, dst_pte, entry); |
| } |
| spin_unlock(&src->page_table_lock); |
| spin_unlock(&dst->page_table_lock); |
| } |
| return 0; |
| |
| nomem: |
| return -ENOMEM; |
| } |
| |
| void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| unsigned long end, struct page *ref_page) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| unsigned long address; |
| pte_t *ptep; |
| pte_t pte; |
| struct page *page; |
| struct page *tmp; |
| struct hstate *h = hstate_vma(vma); |
| unsigned long sz = huge_page_size(h); |
| |
| /* |
| * A page gathering list, protected by per file i_mmap_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); |
| |
| WARN_ON(!is_vm_hugetlb_page(vma)); |
| BUG_ON(start & ~huge_page_mask(h)); |
| BUG_ON(end & ~huge_page_mask(h)); |
| |
| mmu_notifier_invalidate_range_start(mm, start, end); |
| spin_lock(&mm->page_table_lock); |
| for (address = start; address < end; address += sz) { |
| ptep = huge_pte_offset(mm, address); |
| if (!ptep) |
| continue; |
| |
| if (huge_pmd_unshare(mm, &address, ptep)) |
| continue; |
| |
| /* |
| * If a reference page is supplied, it is because a specific |
| * page is being unmapped, not a range. Ensure the page we |
| * are about to unmap is the actual page of interest. |
| */ |
| if (ref_page) { |
| pte = huge_ptep_get(ptep); |
| if (huge_pte_none(pte)) |
| continue; |
| page = pte_page(pte); |
| if (page != ref_page) |
| continue; |
| |
| /* |
| * Mark the VMA as having unmapped its page so that |
| * future faults in this VMA will fail rather than |
| * looking like data was lost |
| */ |
| set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
| } |
| |
| pte = huge_ptep_get_and_clear(mm, address, ptep); |
| if (huge_pte_none(pte)) |
| continue; |
| |
| page = pte_page(pte); |
| if (pte_dirty(pte)) |
| set_page_dirty(page); |
| list_add(&page->lru, &page_list); |
| } |
| spin_unlock(&mm->page_table_lock); |
| flush_tlb_range(vma, start, end); |
| mmu_notifier_invalidate_range_end(mm, start, end); |
| list_for_each_entry_safe(page, tmp, &page_list, lru) { |
| list_del(&page->lru); |
| put_page(page); |
| } |
| } |
| |
| void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| unsigned long end, struct page *ref_page) |
| { |
| spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
| __unmap_hugepage_range(vma, start, end, ref_page); |
| spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
| } |
| |
| /* |
| * This is called when the original mapper is failing to COW a MAP_PRIVATE |
| * mappping it owns the reserve page for. The intention is to unmap the page |
| * from other VMAs and let the children be SIGKILLed if they are faulting the |
| * same region. |
| */ |
| static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, |
| struct page *page, unsigned long address) |
| { |
| struct hstate *h = hstate_vma(vma); |
| struct vm_area_struct *iter_vma; |
| struct address_space *mapping; |
| struct prio_tree_iter iter; |
| pgoff_t pgoff; |
| |
| /* |
| * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
| * from page cache lookup which is in HPAGE_SIZE units. |
| */ |
| address = address & huge_page_mask(h); |
| pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) |
| + (vma->vm_pgoff >> PAGE_SHIFT); |
| mapping = (struct address_space *)page_private(page); |
| |
| vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { |
| /* Do not unmap the current VMA */ |
| if (iter_vma == vma) |
| continue; |
| |
| /* |
| * Unmap the page from other VMAs without their own reserves. |
| * They get marked to be SIGKILLed if they fault in these |
| * areas. This is because a future no-page fault on this VMA |
| * could insert a zeroed page instead of the data existing |
| * from the time of fork. This would look like data corruption |
| */ |
| if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
| unmap_hugepage_range(iter_vma, |
| address, address + huge_page_size(h), |
| page); |
| } |
| |
| return 1; |
| } |
| |
| static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, pte_t pte, |
| struct page *pagecache_page) |
| { |
| struct hstate *h = hstate_vma(vma); |
| struct page *old_page, *new_page; |
| int avoidcopy; |
| int outside_reserve = 0; |
| |
| old_page = pte_page(pte); |
| |
| retry_avoidcopy: |
| /* If no-one else is actually using this page, avoid the copy |
| * and just make the page writable */ |
| avoidcopy = (page_count(old_page) == 1); |
| if (avoidcopy) { |
| set_huge_ptep_writable(vma, address, ptep); |
| return 0; |
| } |
| |
| /* |
| * If the process that created a MAP_PRIVATE mapping is about to |
| * perform a COW due to a shared page count, attempt to satisfy |
| * the allocation without using the existing reserves. The pagecache |
| * page is used to determine if the reserve at this address was |
| * consumed or not. If reserves were used, a partial faulted mapping |
| * at the time of fork() could consume its reserves on COW instead |
| * of the full address range. |
| */ |
| if (!(vma->vm_flags & VM_SHARED) && |
| 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, outside_reserve); |
| |
| if (IS_ERR(new_page)) { |
| page_cache_release(old_page); |
| |
| /* |
| * If a process owning a MAP_PRIVATE mapping fails to COW, |
| * it is due to references held by a child and an insufficient |
| * huge page pool. To guarantee the original mappers |
| * reliability, unmap the page from child processes. The child |
| * may get SIGKILLed if it later faults. |
| */ |
| if (outside_reserve) { |
| BUG_ON(huge_pte_none(pte)); |
| if (unmap_ref_private(mm, vma, old_page, address)) { |
| BUG_ON(page_count(old_page) != 1); |
| BUG_ON(huge_pte_none(pte)); |
| goto retry_avoidcopy; |
| } |
| WARN_ON_ONCE(1); |
| } |
| |
| return -PTR_ERR(new_page); |
| } |
| |
| spin_unlock(&mm->page_table_lock); |
| copy_huge_page(new_page, old_page, address, vma); |
| __SetPageUptodate(new_page); |
| spin_lock(&mm->page_table_lock); |
| |
| ptep = huge_pte_offset(mm, address & huge_page_mask(h)); |
| if (likely(pte_same(huge_ptep_get(ptep), pte))) { |
| /* Break COW */ |
| huge_ptep_clear_flush(vma, address, ptep); |
| set_huge_pte_at(mm, address, ptep, |
| make_huge_pte(vma, new_page, 1)); |
| /* Make the old page be freed below */ |
| new_page = old_page; |
| } |
| page_cache_release(new_page); |
| page_cache_release(old_page); |
| return 0; |
| } |
| |
| /* Return the pagecache page at a given address within a VMA */ |
| static struct page *hugetlbfs_pagecache_page(struct hstate *h, |
| struct vm_area_struct *vma, unsigned long address) |
| { |
| struct address_space *mapping; |
| pgoff_t idx; |
| |
| mapping = vma->vm_file->f_mapping; |
| idx = vma_hugecache_offset(h, vma, address); |
| |
| return find_lock_page(mapping, idx); |
| } |
| |
| static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, int write_access) |
| { |
| struct hstate *h = hstate_vma(vma); |
| int ret = VM_FAULT_SIGBUS; |
| pgoff_t idx; |
| unsigned long size; |
| struct page *page; |
| struct address_space *mapping; |
| pte_t new_pte; |
| |
| /* |
| * Currently, we are forced to kill the process in the event the |
| * original mapper has unmapped pages from the child due to a failed |
| * COW. Warn that such a situation has occured as it may not be obvious |
| */ |
| if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
| printk(KERN_WARNING |
| "PID %d killed due to inadequate hugepage pool\n", |
| current->pid); |
| return ret; |
| } |
| |
| mapping = vma->vm_file->f_mapping; |
| idx = vma_hugecache_offset(h, vma, address); |
| |
| /* |
| * Use page lock to guard against racing truncation |
| * before we get page_table_lock. |
| */ |
| retry: |
| page = find_lock_page(mapping, idx); |
| if (!page) { |
| size = i_size_read(mapping->host) >> huge_page_shift(h); |
| if (idx >= size) |
| goto out; |
| page = alloc_huge_page(vma, address, 0); |
| if (IS_ERR(page)) { |
| ret = -PTR_ERR(page); |
| goto out; |
| } |
| clear_huge_page(page, address, huge_page_size(h)); |
| __SetPageUptodate(page); |
| |
| if (vma->vm_flags & VM_SHARED) { |
| int err; |
| struct inode *inode = mapping->host; |
| |
| err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
| if (err) { |
| put_page(page); |
| if (err == -EEXIST) |
| goto retry; |
| goto out; |
| } |
| |
| spin_lock(&inode->i_lock); |
| inode->i_blocks += blocks_per_huge_page(h); |
| spin_unlock(&inode->i_lock); |
| } else |
| lock_page(page); |
| } |
| |
| /* |
| * If we are going to COW a private mapping later, we examine the |
| * pending reservations for this page now. This will ensure that |
| * any allocations necessary to record that reservation occur outside |
| * the spinlock. |
| */ |
| if (write_access && !(vma->vm_flags & VM_SHARED)) |
| if (vma_needs_reservation(h, vma, address) < 0) { |
| ret = VM_FAULT_OOM; |
| goto backout_unlocked; |
| } |
| |
| spin_lock(&mm->page_table_lock); |
| size = i_size_read(mapping->host) >> huge_page_shift(h); |
| if (idx >= size) |
| goto backout; |
| |
| ret = 0; |
| if (!huge_pte_none(huge_ptep_get(ptep))) |
| goto backout; |
| |
| new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
| && (vma->vm_flags & VM_SHARED))); |
| set_huge_pte_at(mm, address, ptep, new_pte); |
| |
| if (write_access && !(vma->vm_flags & VM_SHARED)) { |
| /* Optimization, do the COW without a second fault */ |
| ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); |
| } |
| |
| spin_unlock(&mm->page_table_lock); |
| unlock_page(page); |
| out: |
| return ret; |
| |
| backout: |
| spin_unlock(&mm->page_table_lock); |
| backout_unlocked: |
| unlock_page(page); |
| put_page(page); |
| goto out; |
| } |
| |
| int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, int write_access) |
| { |
| pte_t *ptep; |
| pte_t entry; |
| int ret; |
| struct page *pagecache_page = NULL; |
| static DEFINE_MUTEX(hugetlb_instantiation_mutex); |
| struct hstate *h = hstate_vma(vma); |
| |
| ptep = huge_pte_alloc(mm, address, huge_page_size(h)); |
| if (!ptep) |
| return VM_FAULT_OOM; |
| |
| /* |
| * Serialize hugepage allocation and instantiation, so that we don't |
| * get spurious allocation failures if two CPUs race to instantiate |
| * the same page in the page cache. |
| */ |
| mutex_lock(&hugetlb_instantiation_mutex); |
| entry = huge_ptep_get(ptep); |
| if (huge_pte_none(entry)) { |
| ret = hugetlb_no_page(mm, vma, address, ptep, write_access); |
| goto out_mutex; |
| } |
| |
| ret = 0; |
| |
| /* |
| * If we are going to COW the mapping later, we examine the pending |
| * reservations for this page now. This will ensure that any |
| * allocations necessary to record that reservation occur outside the |
| * spinlock. For private mappings, we also lookup the pagecache |
| * page now as it is used to determine if a reservation has been |
| * consumed. |
| */ |
| if (write_access && !pte_write(entry)) { |
| if (vma_needs_reservation(h, vma, address) < 0) { |
| ret = VM_FAULT_OOM; |
| goto out_mutex; |
| } |
| |
| if (!(vma->vm_flags & VM_SHARED)) |
| pagecache_page = hugetlbfs_pagecache_page(h, |
| vma, address); |
| } |
| |
| spin_lock(&mm->page_table_lock); |
| /* Check for a racing update before calling hugetlb_cow */ |
| if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) |
| goto out_page_table_lock; |
| |
| |
| if (write_access) { |
| if (!pte_write(entry)) { |
| ret = hugetlb_cow(mm, vma, address, ptep, entry, |
| pagecache_page); |
| goto out_page_table_lock; |
| } |
| entry = pte_mkdirty(entry); |
| } |
| entry = pte_mkyoung(entry); |
| if (huge_ptep_set_access_flags(vma, address, ptep, entry, write_access)) |
| update_mmu_cache(vma, address, entry); |
| |
| out_page_table_lock: |
| spin_unlock(&mm->page_table_lock); |
| |
| if (pagecache_page) { |
| unlock_page(pagecache_page); |
| put_page(pagecache_page); |
| } |
| |
| out_mutex: |
| mutex_unlock(&hugetlb_instantiation_mutex); |
| |
| return ret; |
| } |
| |
| /* Can be overriden by architectures */ |
| __attribute__((weak)) struct page * |
| follow_huge_pud(struct mm_struct *mm, unsigned long address, |
| pud_t *pud, int write) |
| { |
| BUG(); |
| return NULL; |
| } |
| |
| static int huge_zeropage_ok(pte_t *ptep, int write, int shared) |
| { |
| if (!ptep || write || shared) |
| return 0; |
| else |
| return huge_pte_none(huge_ptep_get(ptep)); |
| } |
| |
| 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) |
| { |
| unsigned long pfn_offset; |
| unsigned long vaddr = *position; |
| int remainder = *length; |
| struct hstate *h = hstate_vma(vma); |
| int zeropage_ok = 0; |
| int shared = vma->vm_flags & VM_SHARED; |
| |
| spin_lock(&mm->page_table_lock); |
| while (vaddr < vma->vm_end && remainder) { |
| pte_t *pte; |
| struct page *page; |
| |
| /* |
| * Some archs (sparc64, sh*) have multiple pte_ts to |
| * each hugepage. We have to make * sure we get the |
| * first, for the page indexing below to work. |
| */ |
| pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); |
| if (huge_zeropage_ok(pte, write, shared)) |
| zeropage_ok = 1; |
| |
| if (!pte || |
| (huge_pte_none(huge_ptep_get(pte)) && !zeropage_ok) || |
| (write && !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 (!(ret & VM_FAULT_ERROR)) |
| continue; |
| |
| remainder = 0; |
| if (!i) |
| i = -EFAULT; |
| break; |
| } |
| |
| pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; |
| page = pte_page(huge_ptep_get(pte)); |
| same_page: |
| if (pages) { |
| if (zeropage_ok) |
| pages[i] = ZERO_PAGE(0); |
| else |
| pages[i] = mem_map_offset(page, pfn_offset); |
| get_page(pages[i]); |
| } |
| |
| if (vmas) |
| vmas[i] = vma; |
| |
| vaddr += PAGE_SIZE; |
| ++pfn_offset; |
| --remainder; |
| ++i; |
| if (vaddr < vma->vm_end && remainder && |
| pfn_offset < pages_per_huge_page(h)) { |
| /* |
| * We use pfn_offset to avoid touching the pageframes |
| * of this compound page. |
| */ |
| goto same_page; |
| } |
| } |
| spin_unlock(&mm->page_table_lock); |
| *length = remainder; |
| *position = vaddr; |
| |
| return i; |
| } |
| |
| void hugetlb_change_protection(struct vm_area_struct *vma, |
| unsigned long address, unsigned long end, pgprot_t newprot) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| unsigned long start = address; |
| pte_t *ptep; |
| pte_t pte; |
| struct hstate *h = hstate_vma(vma); |
| |
| BUG_ON(address >= end); |
| flush_cache_range(vma, address, end); |
| |
| spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
| spin_lock(&mm->page_table_lock); |
| for (; address < end; address += huge_page_size(h)) { |
| ptep = huge_pte_offset(mm, address); |
| if (!ptep) |
| continue; |
| if (huge_pmd_unshare(mm, &address, ptep)) |
| continue; |
| if (!huge_pte_none(huge_ptep_get(ptep))) { |
| pte = huge_ptep_get_and_clear(mm, address, ptep); |
| pte = pte_mkhuge(pte_modify(pte, newprot)); |
| set_huge_pte_at(mm, address, ptep, pte); |
| } |
| } |
| spin_unlock(&mm->page_table_lock); |
| spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
| |
| flush_tlb_range(vma, start, end); |
| } |
| |
| int hugetlb_reserve_pages(struct inode *inode, |
| long from, long to, |
| struct vm_area_struct *vma, |
| int acctflag) |
| { |
| long ret, chg; |
| struct hstate *h = hstate_inode(inode); |
| |
| /* |
| * Only apply hugepage reservation if asked. At fault time, an |
| * attempt will be made for VM_NORESERVE to allocate a page |
| * and filesystem quota without using reserves |
| */ |
| if (acctflag & VM_NORESERVE) |
| return 0; |
| |
| /* |
| * Shared mappings base their reservation on the number of pages that |
| * are already allocated on behalf of the file. Private mappings need |
| * to reserve the full area even if read-only as mprotect() may be |
| * called to make the mapping read-write. Assume !vma is a shm mapping |
| */ |
| if (!vma || vma->vm_flags & VM_SHARED) |
| chg = region_chg(&inode->i_mapping->private_list, from, to); |
| else { |
| struct resv_map *resv_map = resv_map_alloc(); |
| if (!resv_map) |
| return -ENOMEM; |
| |
| chg = to - from; |
| |
| set_vma_resv_map(vma, resv_map); |
| set_vma_resv_flags(vma, HPAGE_RESV_OWNER); |
| } |
| |
| if (chg < 0) |
| return chg; |
| |
| /* There must be enough filesystem quota for the mapping */ |
| if (hugetlb_get_quota(inode->i_mapping, chg)) |
| return -ENOSPC; |
| |
| /* |
| * Check enough hugepages are available for the reservation. |
| * Hand back the quota if there are not |
| */ |
| ret = hugetlb_acct_memory(h, chg); |
| if (ret < 0) { |
| hugetlb_put_quota(inode->i_mapping, chg); |
| return ret; |
| } |
| |
| /* |
| * 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_SHARED) |
| region_add(&inode->i_mapping->private_list, from, to); |
| return 0; |
| } |
| |
| void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) |
| { |
| struct hstate *h = hstate_inode(inode); |
| long chg = region_truncate(&inode->i_mapping->private_list, offset); |
| |
| spin_lock(&inode->i_lock); |
| inode->i_blocks -= blocks_per_huge_page(h); |
| spin_unlock(&inode->i_lock); |
| |
| hugetlb_put_quota(inode->i_mapping, (chg - freed)); |
| hugetlb_acct_memory(h, -(chg - freed)); |
| } |