[PATCH 1/2]percpu: introduce read mostly percpu API

[Shaohua Li]

Add a new readmostly percpu section and api, next patch will use it.

Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
---
 include/asm-generic/vmlinux.lds.h |    4 ++++
 include/linux/percpu-defs.h       |    9 +++++++++
 2 files changed, 13 insertions(+)

Index: linux/include/asm-generic/vmlinux.lds.h
===================================================================
--- linux.orig/include/asm-generic/vmlinux.lds.h	2010-10-20 09:32:52.000000000 +0800
+++ linux/include/asm-generic/vmlinux.lds.h	2010-10-20 10:03:38.000000000 +0800
@@ -677,6 +677,8 @@
 				- LOAD_OFFSET) {			\
 		VMLINUX_SYMBOL(__per_cpu_start) = .;			\
 		*(.data..percpu..first)					\
+		. = ALIGN(PAGE_SIZE);					\
+		*(.data..percpu..readmostly)				\
 		*(.data..percpu..page_aligned)				\
 		*(.data..percpu)					\
 		*(.data..percpu..shared_aligned)			\
@@ -703,6 +705,8 @@
 		VMLINUX_SYMBOL(__per_cpu_load) = .;			\
 		VMLINUX_SYMBOL(__per_cpu_start) = .;			\
 		*(.data..percpu..first)					\
+		. = ALIGN(PAGE_SIZE);					\
+		*(.data..percpu..readmostly)				\
 		*(.data..percpu..page_aligned)				\
 		*(.data..percpu)					\
 		*(.data..percpu..shared_aligned)			\
Index: linux/include/linux/percpu-defs.h
===================================================================
--- linux.orig/include/linux/percpu-defs.h	2010-10-20 09:14:27.000000000 +0800
+++ linux/include/linux/percpu-defs.h	2010-10-20 09:17:08.000000000 +0800
@@ -139,6 +139,15 @@
 	__aligned(PAGE_SIZE)
 
 /*
+ * Declaration/definition used for per-CPU variables that must be read mostly.
+ */
+#define DECLARE_PER_CPU_READ_MOSTLY(type, name)			\
+	DECLARE_PER_CPU_SECTION(type, name, "..readmostly")
+
+#define DEFINE_PER_CPU_READ_MOSTLY(type, name)				\
+	DEFINE_PER_CPU_SECTION(type, name, "..readmostly")
+
+/*
  * Intermodule exports for per-CPU variables.  sparse forgets about
  * address space across EXPORT_SYMBOL(), change EXPORT_SYMBOL() to
  * noop if __CHECKER__.


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