| /* |
| * 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/sysctl.h> |
| #include <linux/highmem.h> |
| #include <linux/nodemask.h> |
| #include <linux/pagemap.h> |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| |
| #include <linux/hugetlb.h> |
| |
| const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; |
| static unsigned long nr_huge_pages, free_huge_pages; |
| unsigned long max_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 DEFINE_SPINLOCK(hugetlb_lock); |
| |
| static void enqueue_huge_page(struct page *page) |
| { |
| int nid = page_to_nid(page); |
| list_add(&page->lru, &hugepage_freelists[nid]); |
| free_huge_pages++; |
| free_huge_pages_node[nid]++; |
| } |
| |
| static struct page *dequeue_huge_page(void) |
| { |
| int nid = numa_node_id(); |
| struct page *page = NULL; |
| |
| if (list_empty(&hugepage_freelists[nid])) { |
| for (nid = 0; nid < MAX_NUMNODES; ++nid) |
| if (!list_empty(&hugepage_freelists[nid])) |
| break; |
| } |
| if (nid >= 0 && nid < MAX_NUMNODES && |
| !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]--; |
| } |
| return page; |
| } |
| |
| static struct page *alloc_fresh_huge_page(void) |
| { |
| static int nid = 0; |
| struct page *page; |
| page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN, |
| HUGETLB_PAGE_ORDER); |
| nid = (nid + 1) % num_online_nodes(); |
| if (page) { |
| nr_huge_pages++; |
| nr_huge_pages_node[page_to_nid(page)]++; |
| } |
| return page; |
| } |
| |
| void free_huge_page(struct page *page) |
| { |
| BUG_ON(page_count(page)); |
| |
| INIT_LIST_HEAD(&page->lru); |
| page[1].mapping = NULL; |
| |
| spin_lock(&hugetlb_lock); |
| enqueue_huge_page(page); |
| spin_unlock(&hugetlb_lock); |
| } |
| |
| struct page *alloc_huge_page(void) |
| { |
| struct page *page; |
| int i; |
| |
| spin_lock(&hugetlb_lock); |
| page = dequeue_huge_page(); |
| if (!page) { |
| spin_unlock(&hugetlb_lock); |
| return NULL; |
| } |
| spin_unlock(&hugetlb_lock); |
| set_page_count(page, 1); |
| page[1].mapping = (void *)free_huge_page; |
| for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i) |
| clear_highpage(&page[i]); |
| return page; |
| } |
| |
| static int __init hugetlb_init(void) |
| { |
| unsigned long i; |
| struct page *page; |
| |
| for (i = 0; i < MAX_NUMNODES; ++i) |
| INIT_LIST_HEAD(&hugepage_freelists[i]); |
| |
| for (i = 0; i < max_huge_pages; ++i) { |
| page = alloc_fresh_huge_page(); |
| if (!page) |
| break; |
| spin_lock(&hugetlb_lock); |
| enqueue_huge_page(page); |
| spin_unlock(&hugetlb_lock); |
| } |
| max_huge_pages = free_huge_pages = nr_huge_pages = i; |
| printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); |
| return 0; |
| } |
| module_init(hugetlb_init); |
| |
| static int __init hugetlb_setup(char *s) |
| { |
| if (sscanf(s, "%lu", &max_huge_pages) <= 0) |
| max_huge_pages = 0; |
| return 1; |
| } |
| __setup("hugepages=", hugetlb_setup); |
| |
| #ifdef CONFIG_SYSCTL |
| static void update_and_free_page(struct page *page) |
| { |
| int i; |
| nr_huge_pages--; |
| nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--; |
| 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); |
| set_page_count(&page[i], 0); |
| } |
| set_page_count(page, 1); |
| __free_pages(page, HUGETLB_PAGE_ORDER); |
| } |
| |
| #ifdef CONFIG_HIGHMEM |
| static void try_to_free_low(unsigned long count) |
| { |
| int i, nid; |
| for (i = 0; i < MAX_NUMNODES; ++i) { |
| struct page *page, *next; |
| list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { |
| if (PageHighMem(page)) |
| continue; |
| list_del(&page->lru); |
| update_and_free_page(page); |
| nid = page_zone(page)->zone_pgdat->node_id; |
| free_huge_pages--; |
| free_huge_pages_node[nid]--; |
| if (count >= nr_huge_pages) |
| return; |
| } |
| } |
| } |
| #else |
| static inline void try_to_free_low(unsigned long count) |
| { |
| } |
| #endif |
| |
| static unsigned long set_max_huge_pages(unsigned long count) |
| { |
| while (count > nr_huge_pages) { |
| struct page *page = alloc_fresh_huge_page(); |
| if (!page) |
| return nr_huge_pages; |
| spin_lock(&hugetlb_lock); |
| enqueue_huge_page(page); |
| spin_unlock(&hugetlb_lock); |
| } |
| if (count >= nr_huge_pages) |
| return nr_huge_pages; |
| |
| spin_lock(&hugetlb_lock); |
| try_to_free_low(count); |
| while (count < nr_huge_pages) { |
| struct page *page = dequeue_huge_page(); |
| if (!page) |
| break; |
| update_and_free_page(page); |
| } |
| spin_unlock(&hugetlb_lock); |
| return nr_huge_pages; |
| } |
| |
| int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
| struct file *file, void __user *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
| max_huge_pages = set_max_huge_pages(max_huge_pages); |
| return 0; |
| } |
| #endif /* CONFIG_SYSCTL */ |
| |
| int hugetlb_report_meminfo(char *buf) |
| { |
| return sprintf(buf, |
| "HugePages_Total: %5lu\n" |
| "HugePages_Free: %5lu\n" |
| "Hugepagesize: %5lu kB\n", |
| nr_huge_pages, |
| free_huge_pages, |
| HPAGE_SIZE/1024); |
| } |
| |
| int hugetlb_report_node_meminfo(int nid, char *buf) |
| { |
| return sprintf(buf, |
| "Node %d HugePages_Total: %5u\n" |
| "Node %d HugePages_Free: %5u\n", |
| nid, nr_huge_pages_node[nid], |
| nid, free_huge_pages_node[nid]); |
| } |
| |
| int is_hugepage_mem_enough(size_t size) |
| { |
| return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages; |
| } |
| |
| /* 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); |
| } |
| EXPORT_SYMBOL(hugetlb_total_pages); |
| |
| /* |
| * 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 struct page *hugetlb_nopage(struct vm_area_struct *vma, |
| unsigned long address, int *unused) |
| { |
| BUG(); |
| return NULL; |
| } |
| |
| struct vm_operations_struct hugetlb_vm_ops = { |
| .nopage = hugetlb_nopage, |
| }; |
| |
| static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page) |
| { |
| pte_t entry; |
| |
| if (vma->vm_flags & VM_WRITE) { |
| entry = |
| pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); |
| } else { |
| entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot)); |
| } |
| entry = pte_mkyoung(entry); |
| entry = pte_mkhuge(entry); |
| |
| return 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; |
| |
| for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
| dst_pte = huge_pte_alloc(dst, addr); |
| if (!dst_pte) |
| goto nomem; |
| spin_lock(&src->page_table_lock); |
| src_pte = huge_pte_offset(src, addr); |
| if (src_pte && !pte_none(*src_pte)) { |
| entry = *src_pte; |
| ptepage = pte_page(entry); |
| get_page(ptepage); |
| add_mm_counter(dst, file_rss, HPAGE_SIZE / PAGE_SIZE); |
| set_huge_pte_at(dst, addr, dst_pte, entry); |
| } |
| spin_unlock(&src->page_table_lock); |
| } |
| return 0; |
| |
| nomem: |
| return -ENOMEM; |
| } |
| |
| void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| unsigned long end) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| unsigned long address; |
| pte_t *ptep; |
| pte_t pte; |
| struct page *page; |
| |
| WARN_ON(!is_vm_hugetlb_page(vma)); |
| BUG_ON(start & ~HPAGE_MASK); |
| BUG_ON(end & ~HPAGE_MASK); |
| |
| /* Update high watermark before we lower rss */ |
| update_hiwater_rss(mm); |
| |
| for (address = start; address < end; address += HPAGE_SIZE) { |
| ptep = huge_pte_offset(mm, address); |
| if (! ptep) |
| /* This can happen on truncate, or if an |
| * mmap() is aborted due to an error before |
| * the prefault */ |
| continue; |
| |
| pte = huge_ptep_get_and_clear(mm, address, ptep); |
| if (pte_none(pte)) |
| continue; |
| |
| page = pte_page(pte); |
| put_page(page); |
| add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE)); |
| } |
| flush_tlb_range(vma, start, end); |
| } |
| |
| void zap_hugepage_range(struct vm_area_struct *vma, |
| unsigned long start, unsigned long length) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| |
| spin_lock(&mm->page_table_lock); |
| unmap_hugepage_range(vma, start, start + length); |
| spin_unlock(&mm->page_table_lock); |
| } |
| |
| int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma) |
| { |
| struct mm_struct *mm = current->mm; |
| unsigned long addr; |
| int ret = 0; |
| |
| WARN_ON(!is_vm_hugetlb_page(vma)); |
| BUG_ON(vma->vm_start & ~HPAGE_MASK); |
| BUG_ON(vma->vm_end & ~HPAGE_MASK); |
| |
| hugetlb_prefault_arch_hook(mm); |
| |
| spin_lock(&mm->page_table_lock); |
| for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
| unsigned long idx; |
| pte_t *pte = huge_pte_alloc(mm, addr); |
| struct page *page; |
| |
| if (!pte) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| idx = ((addr - vma->vm_start) >> HPAGE_SHIFT) |
| + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); |
| page = find_get_page(mapping, idx); |
| if (!page) { |
| /* charge the fs quota first */ |
| if (hugetlb_get_quota(mapping)) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| page = alloc_huge_page(); |
| if (!page) { |
| hugetlb_put_quota(mapping); |
| ret = -ENOMEM; |
| goto out; |
| } |
| ret = add_to_page_cache(page, mapping, idx, GFP_ATOMIC); |
| if (! ret) { |
| unlock_page(page); |
| } else { |
| hugetlb_put_quota(mapping); |
| free_huge_page(page); |
| goto out; |
| } |
| } |
| add_mm_counter(mm, file_rss, HPAGE_SIZE / PAGE_SIZE); |
| set_huge_pte_at(mm, addr, pte, make_huge_pte(vma, page)); |
| } |
| out: |
| spin_unlock(&mm->page_table_lock); |
| return ret; |
| } |
| |
| /* |
| * On ia64 at least, it is possible to receive a hugetlb fault from a |
| * stale zero entry left in the TLB from earlier hardware prefetching. |
| * Low-level arch code should already have flushed the stale entry as |
| * part of its fault handling, but we do need to accept this minor fault |
| * and return successfully. Whereas the "normal" case is that this is |
| * an access to a hugetlb page which has been truncated off since mmap. |
| */ |
| int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, int write_access) |
| { |
| int ret = VM_FAULT_SIGBUS; |
| pte_t *pte; |
| |
| spin_lock(&mm->page_table_lock); |
| pte = huge_pte_offset(mm, address); |
| if (pte && !pte_none(*pte)) |
| ret = VM_FAULT_MINOR; |
| spin_unlock(&mm->page_table_lock); |
| 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) |
| { |
| unsigned long vpfn, vaddr = *position; |
| int remainder = *length; |
| |
| BUG_ON(!is_vm_hugetlb_page(vma)); |
| |
| vpfn = vaddr/PAGE_SIZE; |
| spin_lock(&mm->page_table_lock); |
| while (vaddr < vma->vm_end && remainder) { |
| |
| if (pages) { |
| 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 & HPAGE_MASK); |
| |
| /* the hugetlb file might have been truncated */ |
| if (!pte || pte_none(*pte)) { |
| remainder = 0; |
| if (!i) |
| i = -EFAULT; |
| break; |
| } |
| |
| page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)]; |
| |
| WARN_ON(!PageCompound(page)); |
| |
| get_page(page); |
| pages[i] = page; |
| } |
| |
| if (vmas) |
| vmas[i] = vma; |
| |
| vaddr += PAGE_SIZE; |
| ++vpfn; |
| --remainder; |
| ++i; |
| } |
| spin_unlock(&mm->page_table_lock); |
| *length = remainder; |
| *position = vaddr; |
| |
| return i; |
| } |