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-rw-r--r--mm/mincore.c94
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++;
}