page fault scalability patch V10: [7/7] s/390 atomic pte operations

[Christoph Lameter]

Changelog
	* Provide atomic pte operations for s390

Signed-off-by: Christoph Lameter <clameter@xxxxxxx>

Index: linux-2.6.9-rc4/include/asm-s390/pgtable.h
===================================================================
--- linux-2.6.9-rc4.orig/include/asm-s390/pgtable.h	2004-10-10 19:58:24.000000000 -0700
+++ linux-2.6.9-rc4/include/asm-s390/pgtable.h	2004-10-14 12:22:14.000000000 -0700
@@ -567,6 +567,17 @@
 	return pte;
 }

+#define ptep_xchg_flush(__vma, __address, __ptep, __pteval)            \
+({                                                                     \
+	struct mm_struct *__mm = __vma->vm_mm;                          \
+	pte_t __pte;                                                    \
+	spin_lock(&__mm->page_table_lock);                              \
+	__pte = ptep_clear_flush(__vma, __address, __ptep);             \
+	set_pte(__ptep, __pteval);                                      \
+	spin_unlock(&__mm->page_table_lock);                            \
+	__pte;                                                          \
+})
+
 static inline void ptep_set_wrprotect(pte_t *ptep)
 {
 	pte_t old_pte = *ptep;
@@ -778,6 +789,19 @@

 #define kern_addr_valid(addr)   (1)

+/* Atomic PTE operations */
+#define __HAVE_ARCH_ATOMIC_TABLE_OPS
+
+static inline pte_t ptep_xchg(struct mm_struct *mm, unsigned long address, pte_t *ptep, pte_t pteval)
+{
+	return __pte(xchg(ptep, pte_val(pteval)));
+}
+
+static inline int ptep_cmpxchg (struct mm_struct *mm, unsigned long address, pte_t *ptep, pte_t oldval, pte_t newval)
+{
+	return cmpxchg(ptep, pte_val(oldval), pte_val(newval)) == pte_val(oldval);
+}
+
 /*
  * No page table caches to initialise
  */
@@ -791,6 +815,7 @@
 #define __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 #define __HAVE_ARCH_PTEP_CLEAR_FLUSH
+#define __HAVE_ARCH_PTEP_XCHG_FLUSH
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 #define __HAVE_ARCH_PTEP_MKDIRTY
 #define __HAVE_ARCH_PTE_SAME
Index: linux-2.6.9-rc4/include/asm-s390/pgalloc.h
===================================================================
--- linux-2.6.9-rc4.orig/include/asm-s390/pgalloc.h	2004-10-10 19:58:06.000000000 -0700
+++ linux-2.6.9-rc4/include/asm-s390/pgalloc.h	2004-10-14 12:22:14.000000000 -0700
@@ -97,6 +97,10 @@
 	pgd_val(*pgd) = _PGD_ENTRY | __pa(pmd);
 }

+static inline int pgd_test_and_populate(struct mm_struct *mm, pdg_t *pgd, pmd_t *pmd)
+{
+	return cmpxchg(pgd, _PAGE_TABLE_INV, _PGD_ENTRY | __pa(pmd)) == _PAGE_TABLE_INV;
+}
 #endif /* __s390x__ */

 static inline void
@@ -119,6 +123,18 @@
 	pmd_populate_kernel(mm, pmd, (pte_t *)((page-mem_map) << PAGE_SHIFT));
 }

+static inline int
+pmd_test_and_populate(struct mm_struct *mm, pmd_t *pmd, struct page *page)
+{
+	int rc;
+	spin_lock(&mm->page_table_lock);
+
+	rc=pte_same(*pmd, _PAGE_INVALID_EMPTY);
+	if (rc) pmd_populate(mm, pmd, page);
+	spin_unlock(&mm->page_table_lock);
+	return rc;
+}
+
 /*
  * page table entry allocation/free routines.
  */
-
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