mm: introduce wrappers to access mm->nr_ptes

Let's add wrappers for ->nr_ptes with the same interface as for nr_pmd
and nr_pud.

The patch also makes nr_ptes accounting dependent onto CONFIG_MMU.  Page
table accounting doesn't make sense if you don't have page tables.

It's preparation for consolidation of page-table counters in mm_struct.

Link: http://lkml.kernel.org/r/20171006100651.44742-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9af86f39d928..2ca799f0d762 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1680,6 +1680,38 @@ static inline void mm_dec_nr_pmds(struct mm_struct *mm)
 }
 #endif
 
+#ifdef CONFIG_MMU
+static inline void mm_nr_ptes_init(struct mm_struct *mm)
+{
+	atomic_long_set(&mm->nr_ptes, 0);
+}
+
+static inline unsigned long mm_nr_ptes(const struct mm_struct *mm)
+{
+	return atomic_long_read(&mm->nr_ptes);
+}
+
+static inline void mm_inc_nr_ptes(struct mm_struct *mm)
+{
+	atomic_long_inc(&mm->nr_ptes);
+}
+
+static inline void mm_dec_nr_ptes(struct mm_struct *mm)
+{
+	atomic_long_dec(&mm->nr_ptes);
+}
+#else
+static inline void mm_nr_ptes_init(struct mm_struct *mm) {}
+
+static inline unsigned long mm_nr_ptes(const struct mm_struct *mm)
+{
+	return 0;
+}
+
+static inline void mm_inc_nr_ptes(struct mm_struct *mm) {}
+static inline void mm_dec_nr_ptes(struct mm_struct *mm) {}
+#endif
+
 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address);
 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address);