| /* |
| * 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 <linux/mempolicy.h> |
| #include <linux/cpuset.h> |
| #include <linux/mutex.h> |
| |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| |
| #include <linux/hugetlb.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; |
| 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]; |
| /* |
| * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages |
| */ |
| static DEFINE_SPINLOCK(hugetlb_lock); |
| |
| static void clear_huge_page(struct page *page, unsigned long addr) |
| { |
| int i; |
| |
| might_sleep(); |
| for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) { |
| cond_resched(); |
| clear_user_highpage(page + i, addr); |
| } |
| } |
| |
| static void copy_huge_page(struct page *dst, struct page *src, |
| unsigned long addr, struct vm_area_struct *vma) |
| { |
| int i; |
| |
| 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); |
| } |
| } |
| |
| 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(struct vm_area_struct *vma, |
| unsigned long address) |
| { |
| int nid = numa_node_id(); |
| struct page *page = NULL; |
| struct zonelist *zonelist = huge_zonelist(vma, address); |
| struct zone **z; |
| |
| for (z = zonelist->zones; *z; z++) { |
| nid = zone_to_nid(*z); |
| if (cpuset_zone_allowed_softwall(*z, GFP_HIGHUSER) && |
| !list_empty(&hugepage_freelists[nid])) |
| break; |
| } |
| |
| if (*z) { |
| 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 void free_huge_page(struct page *page) |
| { |
| BUG_ON(page_count(page)); |
| |
| INIT_LIST_HEAD(&page->lru); |
| |
| spin_lock(&hugetlb_lock); |
| enqueue_huge_page(page); |
| spin_unlock(&hugetlb_lock); |
| } |
| |
| static int 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 = next_node(nid, node_online_map); |
| if (nid == MAX_NUMNODES) |
| nid = first_node(node_online_map); |
| if (page) { |
| set_compound_page_dtor(page, free_huge_page); |
| spin_lock(&hugetlb_lock); |
| nr_huge_pages++; |
| nr_huge_pages_node[page_to_nid(page)]++; |
| spin_unlock(&hugetlb_lock); |
| put_page(page); /* free it into the hugepage allocator */ |
| return 1; |
| } |
| return 0; |
| } |
| |
| static struct page *alloc_huge_page(struct vm_area_struct *vma, |
| unsigned long addr) |
| { |
| struct page *page; |
| |
| spin_lock(&hugetlb_lock); |
| if (vma->vm_flags & VM_MAYSHARE) |
| resv_huge_pages--; |
| else if (free_huge_pages <= resv_huge_pages) |
| goto fail; |
| |
| page = dequeue_huge_page(vma, addr); |
| if (!page) |
| goto fail; |
| |
| spin_unlock(&hugetlb_lock); |
| set_page_refcounted(page); |
| return page; |
| |
| fail: |
| if (vma->vm_flags & VM_MAYSHARE) |
| resv_huge_pages++; |
| spin_unlock(&hugetlb_lock); |
| return NULL; |
| } |
| |
| static int __init hugetlb_init(void) |
| { |
| unsigned long i; |
| |
| if (HPAGE_SHIFT == 0) |
| return 0; |
| |
| for (i = 0; i < MAX_NUMNODES; ++i) |
| INIT_LIST_HEAD(&hugepage_freelists[i]); |
| |
| for (i = 0; i < max_huge_pages; ++i) { |
| if (!alloc_fresh_huge_page()) |
| break; |
| } |
| 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_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); |
| } |
| page[1].lru.next = NULL; |
| set_page_refcounted(page); |
| __free_pages(page, HUGETLB_PAGE_ORDER); |
| } |
| |
| #ifdef CONFIG_HIGHMEM |
| static void try_to_free_low(unsigned long count) |
| { |
| int i; |
| |
| 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); |
| free_huge_pages--; |
| free_huge_pages_node[page_to_nid(page)]--; |
| 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) { |
| if (!alloc_fresh_huge_page()) |
| return nr_huge_pages; |
| } |
| if (count >= nr_huge_pages) |
| return nr_huge_pages; |
| |
| spin_lock(&hugetlb_lock); |
| count = max(count, resv_huge_pages); |
| try_to_free_low(count); |
| while (count < nr_huge_pages) { |
| struct page *page = dequeue_huge_page(NULL, 0); |
| 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" |
| "HugePages_Rsvd: %5lu\n" |
| "Hugepagesize: %5lu kB\n", |
| nr_huge_pages, |
| free_huge_pages, |
| resv_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]); |
| } |
| |
| /* 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); |
| } |
| |
| /* |
| * 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, |
| int writable) |
| { |
| pte_t entry; |
| |
| if (writable) { |
| 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; |
| } |
| |
| 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(*ptep)); |
| ptep_set_access_flags(vma, address, ptep, entry, 1); |
| update_mmu_cache(vma, address, entry); |
| lazy_mmu_prot_update(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; |
| |
| cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
| |
| for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
| src_pte = huge_pte_offset(src, addr); |
| if (!src_pte) |
| continue; |
| dst_pte = huge_pte_alloc(dst, addr); |
| if (!dst_pte) |
| goto nomem; |
| spin_lock(&dst->page_table_lock); |
| spin_lock(&src->page_table_lock); |
| if (!pte_none(*src_pte)) { |
| if (cow) |
| ptep_set_wrprotect(src, addr, src_pte); |
| entry = *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 mm_struct *mm = vma->vm_mm; |
| unsigned long address; |
| pte_t *ptep; |
| pte_t pte; |
| 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); |
| |
| WARN_ON(!is_vm_hugetlb_page(vma)); |
| BUG_ON(start & ~HPAGE_MASK); |
| BUG_ON(end & ~HPAGE_MASK); |
| |
| spin_lock(&mm->page_table_lock); |
| for (address = start; address < end; address += HPAGE_SIZE) { |
| ptep = huge_pte_offset(mm, address); |
| if (!ptep) |
| continue; |
| |
| if (huge_pmd_unshare(mm, &address, ptep)) |
| continue; |
| |
| pte = huge_ptep_get_and_clear(mm, address, ptep); |
| if (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); |
| 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) |
| { |
| /* |
| * 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. |
| */ |
| 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); |
| } |
| } |
| |
| static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, pte_t pte) |
| { |
| struct page *old_page, *new_page; |
| int avoidcopy; |
| |
| old_page = pte_page(pte); |
| |
| /* 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 VM_FAULT_MINOR; |
| } |
| |
| page_cache_get(old_page); |
| new_page = alloc_huge_page(vma, address); |
| |
| if (!new_page) { |
| page_cache_release(old_page); |
| return VM_FAULT_OOM; |
| } |
| |
| spin_unlock(&mm->page_table_lock); |
| copy_huge_page(new_page, old_page, address, vma); |
| spin_lock(&mm->page_table_lock); |
| |
| ptep = huge_pte_offset(mm, address & HPAGE_MASK); |
| if (likely(pte_same(*ptep, pte))) { |
| /* Break COW */ |
| 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 VM_FAULT_MINOR; |
| } |
| |
| int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, int write_access) |
| { |
| int ret = VM_FAULT_SIGBUS; |
| unsigned long idx; |
| unsigned long size; |
| struct page *page; |
| struct address_space *mapping; |
| pte_t new_pte; |
| |
| mapping = vma->vm_file->f_mapping; |
| idx = ((address - vma->vm_start) >> HPAGE_SHIFT) |
| + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); |
| |
| /* |
| * 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) >> HPAGE_SHIFT; |
| if (idx >= size) |
| goto out; |
| if (hugetlb_get_quota(mapping)) |
| goto out; |
| page = alloc_huge_page(vma, address); |
| if (!page) { |
| hugetlb_put_quota(mapping); |
| ret = VM_FAULT_OOM; |
| goto out; |
| } |
| clear_huge_page(page, address); |
| |
| if (vma->vm_flags & VM_SHARED) { |
| int err; |
| |
| err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
| if (err) { |
| put_page(page); |
| hugetlb_put_quota(mapping); |
| if (err == -EEXIST) |
| goto retry; |
| goto out; |
| } |
| } else |
| lock_page(page); |
| } |
| |
| spin_lock(&mm->page_table_lock); |
| size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
| if (idx >= size) |
| goto backout; |
| |
| ret = VM_FAULT_MINOR; |
| if (!pte_none(*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); |
| } |
| |
| spin_unlock(&mm->page_table_lock); |
| unlock_page(page); |
| out: |
| return ret; |
| |
| backout: |
| spin_unlock(&mm->page_table_lock); |
| hugetlb_put_quota(mapping); |
| 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; |
| static DEFINE_MUTEX(hugetlb_instantiation_mutex); |
| |
| ptep = huge_pte_alloc(mm, address); |
| 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 = *ptep; |
| if (pte_none(entry)) { |
| ret = hugetlb_no_page(mm, vma, address, ptep, write_access); |
| mutex_unlock(&hugetlb_instantiation_mutex); |
| return ret; |
| } |
| |
| ret = VM_FAULT_MINOR; |
| |
| spin_lock(&mm->page_table_lock); |
| /* 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); |
| |
| 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 pfn_offset; |
| unsigned long vaddr = *position; |
| int remainder = *length; |
| |
| 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 & HPAGE_MASK); |
| |
| if (!pte || pte_none(*pte)) { |
| int ret; |
| |
| spin_unlock(&mm->page_table_lock); |
| ret = hugetlb_fault(mm, vma, vaddr, 0); |
| spin_lock(&mm->page_table_lock); |
| if (ret == VM_FAULT_MINOR) |
| continue; |
| |
| remainder = 0; |
| if (!i) |
| i = -EFAULT; |
| break; |
| } |
| |
| pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; |
| page = pte_page(*pte); |
| same_page: |
| if (pages) { |
| get_page(page); |
| pages[i] = page + pfn_offset; |
| } |
| |
| if (vmas) |
| vmas[i] = vma; |
| |
| vaddr += PAGE_SIZE; |
| ++pfn_offset; |
| --remainder; |
| ++i; |
| if (vaddr < vma->vm_end && remainder && |
| pfn_offset < HPAGE_SIZE/PAGE_SIZE) { |
| /* |
| * 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; |
| |
| 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) { |
| ptep = huge_pte_offset(mm, address); |
| if (!ptep) |
| continue; |
| if (huge_pmd_unshare(mm, &address, ptep)) |
| continue; |
| if (!pte_none(*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); |
| lazy_mmu_prot_update(pte); |
| } |
| } |
| spin_unlock(&mm->page_table_lock); |
| spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
| |
| flush_tlb_range(vma, start, end); |
| } |
| |
| 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 guarentee to record the reservation. */ |
| if (&rg->link == head || t < rg->from) { |
| nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
| if (nrg == 0) |
| 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 int hugetlb_acct_memory(long delta) |
| { |
| int ret = -ENOMEM; |
| |
| spin_lock(&hugetlb_lock); |
| if ((delta + resv_huge_pages) <= free_huge_pages) { |
| resv_huge_pages += delta; |
| ret = 0; |
| } |
| spin_unlock(&hugetlb_lock); |
| return ret; |
| } |
| |
| int hugetlb_reserve_pages(struct inode *inode, long from, long to) |
| { |
| long ret, chg; |
| |
| chg = region_chg(&inode->i_mapping->private_list, from, to); |
| if (chg < 0) |
| return chg; |
| ret = hugetlb_acct_memory(chg); |
| if (ret < 0) |
| return ret; |
| region_add(&inode->i_mapping->private_list, from, to); |
| return 0; |
| } |
| |
| void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) |
| { |
| long chg = region_truncate(&inode->i_mapping->private_list, offset); |
| hugetlb_acct_memory(freed - chg); |
| } |