page fault scalability patch V8: [3/7] atomic pte operations for ia64

Changelog
	* Provide atomic pte operations for ia64
	* Enhanced parallelism in page fault handler if applied together
	  with the generic patch

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linus/include/asm-ia64/pgalloc.h
===================================================================
--- linus.orig/include/asm-ia64/pgalloc.h	2004-09-18 14:25:23.000000000 -0700
+++ linus/include/asm-ia64/pgalloc.h	2004-09-18 15:43:25.000000000 -0700
@@ -34,6 +34,10 @@
 #define pmd_quicklist		(local_cpu_data->pmd_quick)
 #define pgtable_cache_size	(local_cpu_data->pgtable_cache_sz)

+/* Empty entries of PMD and PGD */
+#define PMD_NONE       0
+#define PGD_NONE       0
+
 static inline pgd_t*
 pgd_alloc_one_fast (struct mm_struct *mm)
 {
@@ -78,12 +82,19 @@
 	preempt_enable();
 }

+
 static inline void
 pgd_populate (struct mm_struct *mm, pgd_t *pgd_entry, pmd_t *pmd)
 {
 	pgd_val(*pgd_entry) = __pa(pmd);
 }

+/* Atomic populate */
+static inline int
+pgd_test_and_populate (struct mm_struct *mm, pgd_t *pgd_entry, pmd_t *pmd)
+{
+	return ia64_cmpxchg8_acq(pgd_entry,__pa(pmd), PGD_NONE) == PGD_NONE;
+}

 static inline pmd_t*
 pmd_alloc_one_fast (struct mm_struct *mm, unsigned long addr)
@@ -132,6 +143,13 @@
 	pmd_val(*pmd_entry) = page_to_phys(pte);
 }

+/* Atomic populate */
+static inline int
+pmd_test_and_populate (struct mm_struct *mm, pmd_t *pmd_entry, struct page *pte)
+{
+	return ia64_cmpxchg8_acq(pmd_entry, page_to_phys(pte), PMD_NONE) == PMD_NONE;
+}
+
 static inline void
 pmd_populate_kernel (struct mm_struct *mm, pmd_t *pmd_entry, pte_t *pte)
 {
Index: linus/include/asm-ia64/pgtable.h
===================================================================
--- linus.orig/include/asm-ia64/pgtable.h	2004-09-18 14:25:23.000000000 -0700
+++ linus/include/asm-ia64/pgtable.h	2004-09-18 15:43:25.000000000 -0700
@@ -423,6 +423,19 @@
 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 extern void paging_init (void);

+/* Atomic PTE operations */
+static inline pte_t
+ptep_xchg (struct mm_struct *mm, pte_t *ptep, pte_t pteval)
+{
+	return __pte(xchg((long *) ptep, pteval.pte));
+}
+
+static inline int
+ptep_cmpxchg (struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t oldval, pte_t newval)
+{
+	return ia64_cmpxchg8_acq(&ptep->pte, newval.pte, oldval.pte) == oldval.pte;
+}
+
 /*
  * Note: The macros below rely on the fact that MAX_SWAPFILES_SHIFT <= number of
  *	 bits in the swap-type field of the swap pte.  It would be nice to
@@ -558,6 +571,7 @@
 #define __HAVE_ARCH_PTEP_MKDIRTY
 #define __HAVE_ARCH_PTE_SAME
 #define __HAVE_ARCH_PGD_OFFSET_GATE
+#define __HAVE_ARCH_ATOMIC_TABLE_OPS
 #include <asm-generic/pgtable.h>

 #endif /* _ASM_IA64_PGTABLE_H */

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