powerpc/mm: Enable _PAGE_NUMA for book3s

We steal the _PAGE_COHERENCE bit and use that for indicating NUMA ptes.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/pgtable.h

@@ -3,6 +3,7 @@
 #ifdef __KERNEL__
 
 #ifndef __ASSEMBLY__
+#include <linux/mmdebug.h>
 #include <asm/processor.h>		/* For TASK_SIZE */
 #include <asm/mmu.h>
 #include <asm/page.h>
@@ -33,10 +34,73 @@ static inline int pte_dirty(pte_t pte)		{ return pte_val(pte) & _PAGE_DIRTY; }
 static inline int pte_young(pte_t pte)		{ return pte_val(pte) & _PAGE_ACCESSED; }
 static inline int pte_file(pte_t pte)		{ return pte_val(pte) & _PAGE_FILE; }
 static inline int pte_special(pte_t pte)	{ return pte_val(pte) & _PAGE_SPECIAL; }
-static inline int pte_present(pte_t pte)	{ return pte_val(pte) & _PAGE_PRESENT; }
 static inline int pte_none(pte_t pte)		{ return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
 static inline pgprot_t pte_pgprot(pte_t pte)	{ return __pgprot(pte_val(pte) & PAGE_PROT_BITS); }
 
+#ifdef CONFIG_NUMA_BALANCING
+
+static inline int pte_present(pte_t pte)
+{
+	return pte_val(pte) & (_PAGE_PRESENT | _PAGE_NUMA);
+}
+
+#define pte_numa pte_numa
+static inline int pte_numa(pte_t pte)
+{
+	return (pte_val(pte) &
+		(_PAGE_NUMA|_PAGE_PRESENT)) == _PAGE_NUMA;
+}
+
+#define pte_mknonnuma pte_mknonnuma
+static inline pte_t pte_mknonnuma(pte_t pte)
+{
+	pte_val(pte) &= ~_PAGE_NUMA;
+	pte_val(pte) |=  _PAGE_PRESENT | _PAGE_ACCESSED;
+	return pte;
+}
+
+#define pte_mknuma pte_mknuma
+static inline pte_t pte_mknuma(pte_t pte)
+{
+	/*
+	 * We should not set _PAGE_NUMA on non present ptes. Also clear the
+	 * present bit so that hash_page will return 1 and we collect this
+	 * as numa fault.
+	 */
+	if (pte_present(pte)) {
+		pte_val(pte) |= _PAGE_NUMA;
+		pte_val(pte) &= ~_PAGE_PRESENT;
+	} else
+		VM_BUG_ON(1);
+	return pte;
+}
+
+#define pmd_numa pmd_numa
+static inline int pmd_numa(pmd_t pmd)
+{
+	return pte_numa(pmd_pte(pmd));
+}
+
+#define pmd_mknonnuma pmd_mknonnuma
+static inline pmd_t pmd_mknonnuma(pmd_t pmd)
+{
+	return pte_pmd(pte_mknonnuma(pmd_pte(pmd)));
+}
+
+#define pmd_mknuma pmd_mknuma
+static inline pmd_t pmd_mknuma(pmd_t pmd)
+{
+	return pte_pmd(pte_mknuma(pmd_pte(pmd)));
+}
+
+# else
+
+static inline int pte_present(pte_t pte)
+{
+	return pte_val(pte) & _PAGE_PRESENT;
+}
+#endif /* CONFIG_NUMA_BALANCING */
+
 /* Conversion functions: convert a page and protection to a page entry,
  * and a page entry and page directory to the page they refer to.
  *

arch/powerpc/include/asm/pte-hash64.h

@@ -27,6 +27,12 @@
 #define _PAGE_RW		0x0200 /* software: user write access allowed */
 #define _PAGE_BUSY		0x0800 /* software: PTE & hash are busy */
 
+/*
+ * Used for tracking numa faults
+ */
+#define _PAGE_NUMA	0x00000010 /* Gather numa placement stats */
+
+
 /* No separate kernel read-only */
 #define _PAGE_KERNEL_RW		(_PAGE_RW | _PAGE_DIRTY) /* user access blocked by key */
 #define _PAGE_KERNEL_RO		 _PAGE_KERNEL_RW

arch/powerpc/platforms/Kconfig.cputype

@@ -72,6 +72,7 @@ config PPC_BOOK3S_64
 	select PPC_HAVE_PMU_SUPPORT
 	select SYS_SUPPORTS_HUGETLBFS
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if PPC_64K_PAGES
+	select ARCH_SUPPORTS_NUMA_BALANCING
 
 config PPC_BOOK3E_64
 	bool "Embedded processors"