/* * 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, 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); 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, rss, - (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, 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; }