diff options
Diffstat (limited to 'mm/mincore.c')
| -rw-r--r-- | mm/mincore.c | 240 |
1 files changed, 198 insertions, 42 deletions
diff --git a/mm/mincore.c b/mm/mincore.c index 8aca6f7167b..725c8096104 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -7,29 +7,85 @@ /* * The mincore() system call. */ -#include <linux/slab.h> #include <linux/pagemap.h> +#include <linux/gfp.h> #include <linux/mm.h> #include <linux/mman.h> #include <linux/syscalls.h> +#include <linux/swap.h> +#include <linux/swapops.h> +#include <linux/hugetlb.h> #include <asm/uaccess.h> #include <asm/pgtable.h> +static void mincore_hugetlb_page_range(struct vm_area_struct *vma, + unsigned long addr, unsigned long end, + unsigned char *vec) +{ +#ifdef CONFIG_HUGETLB_PAGE + struct hstate *h; + + h = hstate_vma(vma); + while (1) { + unsigned char present; + pte_t *ptep; + /* + * Huge pages are always in RAM for now, but + * theoretically it needs to be checked. + */ + ptep = huge_pte_offset(current->mm, + addr & huge_page_mask(h)); + present = ptep && !huge_pte_none(huge_ptep_get(ptep)); + while (1) { + *vec = present; + vec++; + addr += PAGE_SIZE; + if (addr == end) + return; + /* check hugepage border */ + if (!(addr & ~huge_page_mask(h))) + break; + } + } +#else + BUG(); +#endif +} + /* * Later we can get more picky about what "in core" means precisely. * For now, simply check to see if the page is in the page cache, * and is up to date; i.e. that no page-in operation would be required * at this time if an application were to map and access this page. */ -static unsigned char mincore_page(struct vm_area_struct * vma, - unsigned long pgoff) +static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff) { unsigned char present = 0; - struct address_space * as = vma->vm_file->f_mapping; - struct page * page; + struct page *page; - page = find_get_page(as, pgoff); + /* + * When tmpfs swaps out a page from a file, any process mapping that + * file will not get a swp_entry_t in its pte, but rather it is like + * any other file mapping (ie. marked !present and faulted in with + * tmpfs's .fault). So swapped out tmpfs mappings are tested here. + */ +#ifdef CONFIG_SWAP + if (shmem_mapping(mapping)) { + page = find_get_entry(mapping, pgoff); + /* + * shmem/tmpfs may return swap: account for swapcache + * page too. + */ + if (radix_tree_exceptional_entry(page)) { + swp_entry_t swp = radix_to_swp_entry(page); + page = find_get_page(swap_address_space(swp), swp.val); + } + } else + page = find_get_page(mapping, pgoff); +#else + page = find_get_page(mapping, pgoff); +#endif if (page) { present = PageUptodate(page); page_cache_release(page); @@ -38,51 +94,151 @@ static unsigned char mincore_page(struct vm_area_struct * vma, return present; } +static void mincore_unmapped_range(struct vm_area_struct *vma, + unsigned long addr, unsigned long end, + unsigned char *vec) +{ + unsigned long nr = (end - addr) >> PAGE_SHIFT; + int i; + + if (vma->vm_file) { + pgoff_t pgoff; + + pgoff = linear_page_index(vma, addr); + for (i = 0; i < nr; i++, pgoff++) + vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff); + } else { + for (i = 0; i < nr; i++) + vec[i] = 0; + } +} + +static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd, + unsigned long addr, unsigned long end, + unsigned char *vec) +{ + unsigned long next; + spinlock_t *ptl; + pte_t *ptep; + + ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + do { + pte_t pte = *ptep; + pgoff_t pgoff; + + next = addr + PAGE_SIZE; + if (pte_none(pte)) + mincore_unmapped_range(vma, addr, next, vec); + else if (pte_present(pte)) + *vec = 1; + else if (pte_file(pte)) { + pgoff = pte_to_pgoff(pte); + *vec = mincore_page(vma->vm_file->f_mapping, pgoff); + } else { /* pte is a swap entry */ + swp_entry_t entry = pte_to_swp_entry(pte); + + if (is_migration_entry(entry)) { + /* migration entries are always uptodate */ + *vec = 1; + } else { +#ifdef CONFIG_SWAP + pgoff = entry.val; + *vec = mincore_page(swap_address_space(entry), + pgoff); +#else + WARN_ON(1); + *vec = 1; +#endif + } + } + vec++; + } while (ptep++, addr = next, addr != end); + pte_unmap_unlock(ptep - 1, ptl); +} + +static void mincore_pmd_range(struct vm_area_struct *vma, pud_t *pud, + unsigned long addr, unsigned long end, + unsigned char *vec) +{ + unsigned long next; + pmd_t *pmd; + + pmd = pmd_offset(pud, addr); + do { + next = pmd_addr_end(addr, end); + if (pmd_trans_huge(*pmd)) { + if (mincore_huge_pmd(vma, pmd, addr, next, vec)) { + vec += (next - addr) >> PAGE_SHIFT; + continue; + } + /* fall through */ + } + if (pmd_none_or_trans_huge_or_clear_bad(pmd)) + mincore_unmapped_range(vma, addr, next, vec); + else + mincore_pte_range(vma, pmd, addr, next, vec); + vec += (next - addr) >> PAGE_SHIFT; + } while (pmd++, addr = next, addr != end); +} + +static void mincore_pud_range(struct vm_area_struct *vma, pgd_t *pgd, + unsigned long addr, unsigned long end, + unsigned char *vec) +{ + unsigned long next; + pud_t *pud; + + pud = pud_offset(pgd, addr); + do { + next = pud_addr_end(addr, end); + if (pud_none_or_clear_bad(pud)) + mincore_unmapped_range(vma, addr, next, vec); + else + mincore_pmd_range(vma, pud, addr, next, vec); + vec += (next - addr) >> PAGE_SHIFT; + } while (pud++, addr = next, addr != end); +} + +static void mincore_page_range(struct vm_area_struct *vma, + unsigned long addr, unsigned long end, + unsigned char *vec) +{ + unsigned long next; + pgd_t *pgd; + + pgd = pgd_offset(vma->vm_mm, addr); + do { + next = pgd_addr_end(addr, end); + if (pgd_none_or_clear_bad(pgd)) + mincore_unmapped_range(vma, addr, next, vec); + else + mincore_pud_range(vma, pgd, addr, next, vec); + vec += (next - addr) >> PAGE_SHIFT; + } while (pgd++, addr = next, addr != end); +} + /* * Do a chunk of "sys_mincore()". We've already checked * all the arguments, we hold the mmap semaphore: we should * just return the amount of info we're asked for. */ -static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pages) +static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec) { - unsigned long i, nr, pgoff; - struct vm_area_struct *vma = find_vma(current->mm, addr); + struct vm_area_struct *vma; + unsigned long end; - /* - * find_vma() didn't find anything above us, or we're - * in an unmapped hole in the address space: ENOMEM. - */ + vma = find_vma(current->mm, addr); if (!vma || addr < vma->vm_start) return -ENOMEM; - /* - * Ok, got it. But check whether it's a segment we support - * mincore() on. Right now, we don't do any anonymous mappings. - * - * FIXME: This is just stupid. And returning ENOMEM is - * stupid too. We should just look at the page tables. But - * this is what we've traditionally done, so we'll just - * continue doing it. - */ - if (!vma->vm_file) - return -ENOMEM; - - /* - * Calculate how many pages there are left in the vma, and - * what the pgoff is for our address. - */ - nr = (vma->vm_end - addr) >> PAGE_SHIFT; - if (nr > pages) - nr = pages; - - pgoff = (addr - vma->vm_start) >> PAGE_SHIFT; - pgoff += vma->vm_pgoff; + end = min(vma->vm_end, addr + (pages << PAGE_SHIFT)); - /* And then we just fill the sucker in.. */ - for (i = 0 ; i < nr; i++, pgoff++) - vec[i] = mincore_page(vma, pgoff); + if (is_vm_hugetlb_page(vma)) + mincore_hugetlb_page_range(vma, addr, end, vec); + else + mincore_page_range(vma, addr, end, vec); - return nr; + return (end - addr) >> PAGE_SHIFT; } /* @@ -109,8 +265,8 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag * mapped * -EAGAIN - A kernel resource was temporarily unavailable. */ -asmlinkage long sys_mincore(unsigned long start, size_t len, - unsigned char __user * vec) +SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len, + unsigned char __user *, vec) { long retval; unsigned long pages; @@ -142,7 +298,7 @@ asmlinkage long sys_mincore(unsigned long start, size_t len, * the temporary buffer size. */ down_read(¤t->mm->mmap_sem); - retval = do_mincore(start, tmp, min(pages, PAGE_SIZE)); + retval = do_mincore(start, min(pages, PAGE_SIZE), tmp); up_read(¤t->mm->mmap_sem); if (retval <= 0) |