[PATCHv4 01/12] asm-generic: Provide generic_pmdp_establish()

Kirill A. Shutemov
2017-12-13T10:59:08Z

This is an implementation of pmdp_establish() that is only suitable for
an architecture that doesn't have hardware dirty/accessed bits. In this
case we can't race with CPU which sets these bits and non-atomic
approach is fine.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
include/asm-generic/pgtable.h | 15 +++++++++++++++
1 file changed, 15 insertions(+)

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index b234d54f2cb6..ae83b14200b8 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -309,6 +309,21 @@ extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp);
#endif

+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/*
+ * This is an implementation of pmdp_establish() that is only suitable for an
+ * architecture that doesn't have hardware dirty/accessed bits. In this case we
+ * can't race with CPU which sets these bits and non-atomic aproach is fine.
+ */
+static inline pmd_t generic_pmdp_establish(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp, pmd_t pmd)
+{
+ pmd_t old_pmd = *pmdp;
+ set_pmd_at(vma->vm_mm, address, pmdp, pmd);
+ return old_pmd;
+}
+#endif
+
#ifndef __HAVE_ARCH_PMDP_INVALIDATE
extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp);
--
2.15.0