diff options
Diffstat (limited to 'mm')
-rw-r--r-- | mm/mincore.c | 94 |
1 files changed, 81 insertions, 13 deletions
diff --git a/mm/mincore.c b/mm/mincore.c index f0f91461a9f4..218099b5ed31 100644 --- a/mm/mincore.c +++ b/mm/mincore.c @@ -42,14 +42,72 @@ static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr, return 0; } -static int mincore_unmapped_range(unsigned long addr, unsigned long end, - struct mm_walk *walk) +/* + * 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 address_space *mapping, pgoff_t pgoff) +{ + unsigned char present = 0; + struct page *page; + + /* + * 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 (xa_is_value(page)) { + swp_entry_t swp = radix_to_swp_entry(page); + page = find_get_page(swap_address_space(swp), + swp_offset(swp)); + } + } else + page = find_get_page(mapping, pgoff); +#else + page = find_get_page(mapping, pgoff); +#endif + if (page) { + present = PageUptodate(page); + put_page(page); + } + + return present; +} + +static int __mincore_unmapped_range(unsigned long addr, unsigned long end, + struct vm_area_struct *vma, unsigned char *vec) { - unsigned char *vec = walk->private; unsigned long nr = (end - addr) >> PAGE_SHIFT; + int i; - memset(vec, 0, nr); - walk->private += nr; + 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; + } + return nr; +} + +static int mincore_unmapped_range(unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + walk->private += __mincore_unmapped_range(addr, end, + walk->vma, walk->private); return 0; } @@ -69,9 +127,8 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, goto out; } - /* We'll consider a THP page under construction to be there */ if (pmd_trans_unstable(pmd)) { - memset(vec, 1, nr); + __mincore_unmapped_range(addr, end, vma, vec); goto out; } @@ -80,17 +137,28 @@ static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, pte_t pte = *ptep; if (pte_none(pte)) - *vec = 0; + __mincore_unmapped_range(addr, addr + PAGE_SIZE, + vma, vec); else if (pte_present(pte)) *vec = 1; else { /* pte is a swap entry */ swp_entry_t entry = pte_to_swp_entry(pte); - /* - * migration or hwpoison entries are always - * uptodate - */ - *vec = !!non_swap_entry(entry); + if (non_swap_entry(entry)) { + /* + * migration or hwpoison entries are always + * uptodate + */ + *vec = 1; + } else { +#ifdef CONFIG_SWAP + *vec = mincore_page(swap_address_space(entry), + swp_offset(entry)); +#else + WARN_ON(1); + *vec = 1; +#endif + } } vec++; } |