On 02/26/2016 10:53 AM, Will Deacon wrote:

On Mon, Feb 22, 2016 at 05:58:23PM -0800, David Daney wrote:

quoted

From: Ganapatrao Kulkarni <redacted>

Enable NUMA balancing for arm64 platforms.
Add pte, pmd protnone helpers for use by automatic NUMA balancing.

Reviewed-by: Robert Richter <rrichter-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Ganapatrao Kulkarni <redacted>
Signed-off-by: David Daney <david.daney-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
---
  arch/arm64/Kconfig               |  1 +
  arch/arm64/include/asm/pgtable.h | 15 +++++++++++++++
  2 files changed, 16 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9f0972a..6e22503 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -11,6 +11,7 @@ config ARM64
  	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
  	select ARCH_USE_CMPXCHG_LOCKREF
  	select ARCH_SUPPORTS_ATOMIC_RMW
+	select ARCH_SUPPORTS_NUMA_BALANCING
  	select ARCH_WANT_OPTIONAL_GPIOLIB
  	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION
  	select ARCH_WANT_FRAME_POINTERS

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index bf464de..5af9db2 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h

@@ -346,6 +346,21 @@ static inline pgprot_t mk_sect_prot(pgprot_t prot)
  	return __pgprot(pgprot_val(prot) & ~PTE_TABLE_BIT);
  }

+#ifdef CONFIG_NUMA_BALANCING
+/*
+ * See the comment in include/asm-generic/pgtable.h
+ */
+static inline int pte_protnone(pte_t pte)
+{
+	return (pte_val(pte) & (PTE_VALID | PTE_PROT_NONE)) == PTE_PROT_NONE;
+}
+
+static inline int pmd_protnone(pmd_t pmd)
+{
+	return pte_protnone(pmd_pte(pmd));
+}
+#endif

Can these not be macros, like our other pte_* and pmd_* predicates in
this header file?

They probably could be.  However there is precedence for the static 
inline form:

$ git grep pte_protnone | grep '\.h' | grep -v return
arch/arm64/include/asm/pgtable.h:static inline int pte_protnone(pte_t pte)
arch/powerpc/include/asm/book3s/64/hash.h:static inline int 
pte_protnone(pte_t pte)
arch/powerpc/include/asm/nohash/pgtable.h:static inline int 
pte_protnone(pte_t pte)
arch/s390/include/asm/pgtable.h:static inline int pte_protnone(pte_t pte)
arch/x86/include/asm/pgtable.h:static inline int pte_protnone(pte_t pte)
include/asm-generic/pgtable.h:static inline int pte_protnone(pte_t pte)


Actually I am a little surprised that all the arm64 pte_* and pmd_* 
things are not written as static inline to achieve added type safety. 
The generated code should be identical.

Will

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