+ define-new-percpu-interface-for-shared-data.patch added to -mm tree

PATCH New [email protected] 2 participants 2 messages May 23, 2007 – Jun 13, 2007

Subsystems (10)

Arm (32-bit) PowerPC MIPS s390 +6 more subsystems

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2007-05-23 17:48 UTC #0 lore raw

The patch titled
Define new percpu interface for shared data
has been added to the -mm tree. Its filename is
define-new-percpu-interface-for-shared-data.patch

*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this

------------------------------------------------------
Subject: Define new percpu interface for shared data
From: Fenghua Yu <[email protected]>

per cpu data section contains two types of data. One set which is exclusively accessed by the local cpu and the other set which is per cpu, but also shared by remote cpus. In the current kernel, these two sets are not clearely separated out. This can potentially cause the same data cacheline shared between the two sets of data, which will result in unnecessary bouncing of the cacheline between cpus.

One way to fix the problem is to cacheline align the remotely accessed per cpu data, both at the beginning and at the end. Because of the padding at both ends, this will likely cause some memory wastage and also the interface to achieve this is not clean.

This patch:

Moves the remotely accessed per cpu data (which is currently marked as ____cacheline_aligned_in_smp) into a different section, where all the data elements are cacheline aligned. And as such, this differentiates the local only data and remotely accessed data cleanly.

Signed-off-by Fenghua Yu <[email protected]>

Acked-by Suresh Siddha <[email protected]>

Cc Rusty Russell <[email protected]>

Cc Christoph Lameter <[email protected]>

Cc <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

---

 arch/alpha/kernel/vmlinux.lds.S   |    5 +----
 arch/arm/kernel/vmlinux.lds.S     |    1 +
 arch/cris/arch-v32/vmlinux.lds.S  |    5 +----
 arch/frv/kernel/vmlinux.lds.S     |    5 +----
 arch/i386/kernel/vmlinux.lds.S    |    7 +------
 arch/ia64/kernel/vmlinux.lds.S    |    1 +
 arch/m32r/kernel/vmlinux.lds.S    |    5 +----
 arch/mips/kernel/vmlinux.lds.S    |    5 +----
 arch/parisc/kernel/vmlinux.lds.S  |    7 +++----
 arch/powerpc/kernel/vmlinux.lds.S |    7 +------
 arch/ppc/kernel/vmlinux.lds.S     |    5 +----
 arch/s390/kernel/vmlinux.lds.S    |    5 +----
 arch/sh/kernel/vmlinux.lds.S      |    5 +----
 arch/sh64/kernel/vmlinux.lds.S    |    5 +----
 arch/sparc/kernel/vmlinux.lds.S   |    5 +----
 arch/sparc64/kernel/vmlinux.lds.S |    5 +----
 arch/x86_64/kernel/vmlinux.lds.S  |    6 ++----
 arch/xtensa/kernel/vmlinux.lds.S  |    5 +----
 include/asm-generic/percpu.h      |    8 ++++++++
 include/asm-generic/vmlinux.lds.h |    8 ++++++++
 include/asm-i386/percpu.h         |    5 +++++
 include/asm-ia64/percpu.h         |   10 ++++++++++
 include/asm-powerpc/percpu.h      |    7 +++++++
 include/asm-s390/percpu.h         |    7 +++++++
 include/asm-sparc64/percpu.h      |    7 +++++++
 include/asm-x86_64/percpu.h       |    7 +++++++
 26 files changed, 80 insertions(+), 68 deletions(-)

arch/alpha/kernel/vmlinux.lds.S renamed from arch/alpha/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/alpha/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/alpha/kernel/vmlinux.lds.S
@@ -69,10 +69,7 @@ SECTIONS
   . = ALIGN(8);
   SECURITY_INIT
 
-  . = ALIGN(8192);
-  __per_cpu_start = .;
-  .data.percpu : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(8192)
 
   . = ALIGN(2*8192);
   __init_end = .;

arch/arm/kernel/vmlinux.lds.S renamed from arch/arm/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -0

diff -puN arch/arm/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/arm/kernel/vmlinux.lds.S
@@ -66,6 +66,7 @@ SECTIONS
 		. = ALIGN(4096);
 		__per_cpu_start = .;
 			*(.data.percpu)
+			*(.data.percpu.shared_aligned)
 		__per_cpu_end = .;
 #ifndef CONFIG_XIP_KERNEL
 		__init_begin = _stext;

arch/cris/arch-v32/vmlinux.lds.S renamed from arch/cris/arch-v32/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/cris/arch-v32/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/cris/arch-v32/vmlinux.lds.S
@@ -91,10 +91,7 @@ SECTIONS
 	}
 	SECURITY_INIT
 
-	. =  ALIGN (8192);
-	__per_cpu_start = .;
-	.data.percpu  : { *(.data.percpu) }
-	__per_cpu_end = .;
+	PERCPU(8192)
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	.init.ramfs : {

arch/frv/kernel/vmlinux.lds.S renamed from arch/frv/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/frv/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/frv/kernel/vmlinux.lds.S
@@ -57,10 +57,7 @@ SECTIONS
   __alt_instructions_end = .;
  .altinstr_replacement : { *(.altinstr_replacement) }
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
 
 #ifdef CONFIG_BLK_DEV_INITRD
   . = ALIGN(4096);

arch/i386/kernel/vmlinux.lds.S renamed from arch/i386/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -6

diff -puN arch/i386/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/i386/kernel/vmlinux.lds.S
@@ -179,12 +179,7 @@ SECTIONS
 	__initramfs_end = .;
   }
 #endif
-  . = ALIGN(4096);
-  .data.percpu  : AT(ADDR(.data.percpu) - LOAD_OFFSET) {
-	__per_cpu_start = .;
-	*(.data.percpu)
-	__per_cpu_end = .;
-  }
+  PERCPU(4096)
   . = ALIGN(4096);
   /* freed after init ends here */

arch/ia64/kernel/vmlinux.lds.S renamed from arch/ia64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -0

diff -puN arch/ia64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/ia64/kernel/vmlinux.lds.S
@@ -206,6 +206,7 @@ SECTIONS
 	{
 		__per_cpu_start = .;
 		*(.data.percpu)
+		*(.data.percpu.shared_aligned)
 		__per_cpu_end = .;
 	}
   . = __phys_per_cpu_start + PERCPU_PAGE_SIZE;	/* ensure percpu data fits

arch/m32r/kernel/vmlinux.lds.S renamed from arch/m32r/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/m32r/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/m32r/kernel/vmlinux.lds.S
@@ -110,10 +110,7 @@ SECTIONS
   __initramfs_end = .;
 #endif
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
   . = ALIGN(4096);
   __init_end = .;
   /* freed after init ends here */

arch/mips/kernel/vmlinux.lds.S renamed from arch/mips/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/mips/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/mips/kernel/vmlinux.lds.S
@@ -119,10 +119,7 @@ SECTIONS
   .init.ramfs : { *(.init.ramfs) }
   __initramfs_end = .;
 #endif
-  . = ALIGN(_PAGE_SIZE);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(_PAGE_SIZE)
   . = ALIGN(_PAGE_SIZE);
   __init_end = .;
   /* freed after init ends here */

arch/parisc/kernel/vmlinux.lds.S renamed from arch/parisc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +3 -4

diff -puN arch/parisc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/parisc/kernel/vmlinux.lds.S
@@ -181,10 +181,9 @@ SECTIONS
   .init.ramfs : { *(.init.ramfs) }
   __initramfs_end = .;
 #endif
-  . = ALIGN(ASM_PAGE_SIZE);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+
+  PERCPU(ASM_PAGE_SIZE)
+
   . = ALIGN(ASM_PAGE_SIZE);
   __init_end = .;
   /* freed after init ends here */

arch/powerpc/kernel/vmlinux.lds.S renamed from arch/powerpc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -6

diff -puN arch/powerpc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/powerpc/kernel/vmlinux.lds.S
@@ -139,12 +139,7 @@ SECTIONS
 		__initramfs_end = .;
 	}
 #endif
-	. = ALIGN(PAGE_SIZE);
-	.data.percpu : {
-		__per_cpu_start = .;
-		*(.data.percpu)
-		__per_cpu_end = .;
-	}
+	PERCPU(PAGE_SIZE)
 
 	. = ALIGN(8);
 	.machine.desc : {

arch/ppc/kernel/vmlinux.lds.S renamed from arch/ppc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/ppc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/ppc/kernel/vmlinux.lds.S
@@ -130,10 +130,7 @@ SECTIONS
   __ftr_fixup : { *(__ftr_fixup) }
   __stop___ftr_fixup = .;
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
 
 #ifdef CONFIG_BLK_DEV_INITRD
   . = ALIGN(4096);

arch/s390/kernel/vmlinux.lds.S renamed from arch/s390/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/s390/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/s390/kernel/vmlinux.lds.S
@@ -107,10 +107,7 @@ SECTIONS
   . = ALIGN(2);
   __initramfs_end = .;
 #endif
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
   . = ALIGN(4096);
   __init_end = .;
   /* freed after init ends here */

arch/sh/kernel/vmlinux.lds.S renamed from arch/sh/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/sh/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/sh/kernel/vmlinux.lds.S
@@ -60,10 +60,7 @@ SECTIONS
   . = ALIGN(PAGE_SIZE);
   __nosave_end = .;
 
-  . = ALIGN(PAGE_SIZE);
-  __per_cpu_start = .;
-  .data.percpu : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(PAGE_SIZE)
   .data.cacheline_aligned : { *(.data.cacheline_aligned) }
 
   _edata = .;			/* End of data section */

arch/sh64/kernel/vmlinux.lds.S renamed from arch/sh64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/sh64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/sh64/kernel/vmlinux.lds.S
@@ -85,10 +85,7 @@ SECTIONS
   . = ALIGN(PAGE_SIZE);
   .data.page_aligned : C_PHYS(.data.page_aligned) { *(.data.page_aligned) }
 
-  . = ALIGN(PAGE_SIZE);
-  __per_cpu_start = .;
-  .data.percpu : C_PHYS(.data.percpu) { *(.data.percpu) }
-  __per_cpu_end = . ;
+  PERCPU(PAGE_SIZE)
   .data.cacheline_aligned : C_PHYS(.data.cacheline_aligned) { *(.data.cacheline_aligned) }
 
   _edata = .;			/* End of data section */

arch/sparc/kernel/vmlinux.lds.S renamed from arch/sparc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/sparc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/sparc/kernel/vmlinux.lds.S
@@ -65,10 +65,7 @@ SECTIONS
   __initramfs_end = .;
 #endif
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
   . = ALIGN(4096);
   __init_end = .;
   . = ALIGN(32);

arch/sparc64/kernel/vmlinux.lds.S renamed from arch/sparc64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/sparc64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/sparc64/kernel/vmlinux.lds.S
@@ -89,10 +89,7 @@ SECTIONS
   __initramfs_end = .;
 #endif
 
-  . = ALIGN(8192);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(8192)
   . = ALIGN(8192);
   __init_end = .;
   __bss_start = .;

arch/x86_64/kernel/vmlinux.lds.S renamed from arch/x86_64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +2 -4

diff -puN arch/x86_64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/x86_64/kernel/vmlinux.lds.S
@@ -203,10 +203,8 @@ SECTIONS
   __initramfs_end = .;
 #endif
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : AT(ADDR(.data.percpu) - LOAD_OFFSET) { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
+
   . = ALIGN(4096);
   __init_end = .;

arch/xtensa/kernel/vmlinux.lds.S renamed from arch/xtensa/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data +1 -4

diff -puN arch/xtensa/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data arch/xtensa/kernel/vmlinux.lds.S
@@ -200,10 +200,7 @@ SECTIONS
   __ftr_fixup : { *(__ftr_fixup) }
   __stop___ftr_fixup = .;
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
 
 #ifdef CONFIG_BLK_DEV_INITRD
   . = ALIGN(4096);

include/asm-generic/percpu.h renamed from include/asm-generic/percpu.h~define-new-percpu-interface-for-shared-data +8 -0

diff -puN include/asm-generic/percpu.h~define-new-percpu-interface-for-shared-data include/asm-generic/percpu.h
@@ -14,6 +14,11 @@ extern unsigned long __per_cpu_offset[NR
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 /* var is in discarded region: offset to particular copy we want */
 #define per_cpu(var, cpu) (*({				\
 	extern int simple_identifier_##var(void);	\

@@ -34,6 +39,9 @@ do {								\
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
+
 #define per_cpu(var, cpu)			(*((void)(cpu), &per_cpu__##var))
 #define __get_cpu_var(var)			per_cpu__##var
 #define __raw_get_cpu_var(var)			per_cpu__##var

include/asm-generic/vmlinux.lds.h renamed from include/asm-generic/vmlinux.lds.h~define-new-percpu-interface-for-shared-data +8 -0

diff -puN include/asm-generic/vmlinux.lds.h~define-new-percpu-interface-for-shared-data include/asm-generic/vmlinux.lds.h
@@ -263,3 +263,11 @@
   	*(.initcall7.init)						\
   	*(.initcall7s.init)
 
+#define PERCPU(align)							\
+	. = ALIGN(align);						\
+	__per_cpu_start = .;						\
+	.data.percpu  : AT(ADDR(.data.percpu) - LOAD_OFFSET) {		\
+		*(.data.percpu)						\
+		*(.data.percpu.shared_aligned)				\
+	}								\
+	__per_cpu_end = .;

include/asm-i386/percpu.h renamed from include/asm-i386/percpu.h~define-new-percpu-interface-for-shared-data +5 -0

diff -puN include/asm-i386/percpu.h~define-new-percpu-interface-for-shared-data include/asm-i386/percpu.h
@@ -54,6 +54,11 @@ extern unsigned long __per_cpu_offset[];
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 /* We can use this directly for local CPU (faster). */
 DECLARE_PER_CPU(unsigned long, this_cpu_off);

include/asm-ia64/percpu.h renamed from include/asm-ia64/percpu.h~define-new-percpu-interface-for-shared-data +10 -0

diff -puN include/asm-ia64/percpu.h~define-new-percpu-interface-for-shared-data include/asm-ia64/percpu.h
@@ -29,6 +29,16 @@
 	__attribute__((__section__(".data.percpu")))		\
 	__SMALL_ADDR_AREA __typeof__(type) per_cpu__##name
 
+#ifdef CONFIG_SMP
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)			\
+	__attribute__((__section__(".data.percpu.shared_aligned")))	\
+	__SMALL_ADDR_AREA __typeof__(type) per_cpu__##name		\
+	____cacheline_aligned_in_smp
+#else
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+	DEFINE_PER_CPU(type, name)
+#endif
+
 /*
  * Pretty much a literal copy of asm-generic/percpu.h, except that percpu_modcopy() is an
  * external routine, to avoid include-hell.

include/asm-powerpc/percpu.h renamed from include/asm-powerpc/percpu.h~define-new-percpu-interface-for-shared-data +7 -0

diff -puN include/asm-powerpc/percpu.h~define-new-percpu-interface-for-shared-data include/asm-powerpc/percpu.h
@@ -20,6 +20,11 @@
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 /* var is in discarded region: offset to particular copy we want */
 #define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset(cpu)))
 #define __get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))

@@ -40,6 +45,8 @@ extern void setup_per_cpu_areas(void);
 
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
 
 #define per_cpu(var, cpu)			(*((void)(cpu), &per_cpu__##var))
 #define __get_cpu_var(var)			per_cpu__##var

include/asm-s390/percpu.h renamed from include/asm-s390/percpu.h~define-new-percpu-interface-for-shared-data +7 -0

diff -puN include/asm-s390/percpu.h~define-new-percpu-interface-for-shared-data include/asm-s390/percpu.h
@@ -41,6 +41,11 @@ extern unsigned long __per_cpu_offset[NR
     __attribute__((__section__(".data.percpu"))) \
     __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 #define __get_cpu_var(var) __reloc_hide(var,S390_lowcore.percpu_offset)
 #define __raw_get_cpu_var(var) __reloc_hide(var,S390_lowcore.percpu_offset)
 #define per_cpu(var,cpu) __reloc_hide(var,__per_cpu_offset[cpu])

@@ -59,6 +64,8 @@ do {								\
 
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
 
 #define __get_cpu_var(var) __reloc_hide(var,0)
 #define __raw_get_cpu_var(var) __reloc_hide(var,0)

include/asm-sparc64/percpu.h renamed from include/asm-sparc64/percpu.h~define-new-percpu-interface-for-shared-data +7 -0

diff -puN include/asm-sparc64/percpu.h~define-new-percpu-interface-for-shared-data include/asm-sparc64/percpu.h
@@ -17,6 +17,11 @@ extern unsigned long __per_cpu_shift;
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 register unsigned long __local_per_cpu_offset asm("g5");
 
 /* var is in discarded region: offset to particular copy we want */

@@ -36,6 +41,8 @@ do {								\
 
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
 
 #define per_cpu(var, cpu)			(*((void)cpu, &per_cpu__##var))
 #define __get_cpu_var(var)			per_cpu__##var

include/asm-x86_64/percpu.h renamed from include/asm-x86_64/percpu.h~define-new-percpu-interface-for-shared-data +7 -0

diff -puN include/asm-x86_64/percpu.h~define-new-percpu-interface-for-shared-data include/asm-x86_64/percpu.h
@@ -20,6 +20,11 @@
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_internodealigned_in_smp
+
 /* var is in discarded region: offset to particular copy we want */
 #define per_cpu(var, cpu) (*({				\
 	extern int simple_identifier_##var(void);	\

@@ -46,6 +51,8 @@ extern void setup_per_cpu_areas(void);
 
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
 
 #define per_cpu(var, cpu)			(*((void)(cpu), &per_cpu__##var))
 #define __get_cpu_var(var)			per_cpu__##var

Patches currently in -mm which might be from [email protected] are

define-new-percpu-interface-for-shared-data.patch use-the-new-percpu-interface-for-shared-data.patch

Fenghua Yu

2007-06-13 19:01 UTC #1 lore raw

PATCH 1/2 : define new percpu interface for shared data - version 4

Changes from previous version:
Fix a per_cpu_start and per_cpu_end absolute symbols bug on i386.

This patch:

Signed-off-by Fenghua Yu <[email protected]>

Acked-by Suresh Siddha <[email protected]>

Cc Rusty Russell <[email protected]>

Cc Christoph Lameter <[email protected]>

Cc <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

---

 arch/alpha/kernel/vmlinux.lds.S   |    5 +----
 arch/arm/kernel/vmlinux.lds.S     |    1 +
 arch/cris/arch-v32/vmlinux.lds.S  |    5 +----
 arch/frv/kernel/vmlinux.lds.S     |    5 +----
 arch/i386/kernel/vmlinux.lds.S    |    1 +
 arch/ia64/kernel/vmlinux.lds.S    |    1 +
 arch/m32r/kernel/vmlinux.lds.S    |    5 +----
 arch/mips/kernel/vmlinux.lds.S    |    5 +----
 arch/parisc/kernel/vmlinux.lds.S  |    7 +++----
 arch/powerpc/kernel/vmlinux.lds.S |    1 +
 arch/ppc/kernel/vmlinux.lds.S     |    5 +----
 arch/s390/kernel/vmlinux.lds.S    |    5 +----
 arch/sh/kernel/vmlinux.lds.S      |    5 +----
 arch/sh64/kernel/vmlinux.lds.S    |    5 ++++-
 arch/sparc/kernel/vmlinux.lds.S   |    5 +----
 arch/sparc64/kernel/vmlinux.lds.S |    6 ++----
 arch/x86_64/kernel/vmlinux.lds.S  |    6 ++----
 arch/xtensa/kernel/vmlinux.lds.S  |    5 +----
 include/asm-generic/percpu.h      |    8 ++++++++
 include/asm-generic/vmlinux.lds.h |    8 ++++++++
 include/asm-i386/percpu.h         |    5 +++++
 include/asm-ia64/percpu.h         |   10 ++++++++++
 include/asm-powerpc/percpu.h      |    7 +++++++
 include/asm-s390/percpu.h         |    7 +++++++
 include/asm-sparc64/percpu.h      |    7 +++++++
 include/asm-x86_64/percpu.h       |    7 +++++++
 26 files changed, 84 insertions(+), 53 deletions(-)

arch/alpha/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/alpha/kernel/vmlinux.lds.S linux-2.6.21.1/arch/alpha/kernel/vmlinux.lds.S
@@ -69,10 +69,7 @@ SECTIONS
   . = ALIGN(8);
   SECURITY_INIT
 
-  . = ALIGN(8192);
-  __per_cpu_start = .;
-  .data.percpu : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(8192)
 
   . = ALIGN(2*8192);
   __init_end = .;

arch/arm/kernel/vmlinux.lds.S +1 -0

diff -Nurp linux-2.6.21.0/arch/arm/kernel/vmlinux.lds.S linux-2.6.21.1/arch/arm/kernel/vmlinux.lds.S
@@ -66,6 +66,7 @@ SECTIONS
 		. = ALIGN(4096);
 		__per_cpu_start = .;
 			*(.data.percpu)
+			*(.data.percpu.shared_aligned)
 		__per_cpu_end = .;
 #ifndef CONFIG_XIP_KERNEL
 		__init_begin = _stext;

arch/cris/arch-v32/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/cris/arch-v32/vmlinux.lds.S linux-2.6.21.1/arch/cris/arch-v32/vmlinux.lds.S
@@ -91,10 +91,7 @@ SECTIONS
 	}
 	SECURITY_INIT
 
-	. =  ALIGN (8192);
-	__per_cpu_start = .;
-	.data.percpu  : { *(.data.percpu) }
-	__per_cpu_end = .;
+	PERCPU(8192)
 
 #ifdef CONFIG_BLK_DEV_INITRD
 	.init.ramfs : {

arch/frv/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/frv/kernel/vmlinux.lds.S linux-2.6.21.1/arch/frv/kernel/vmlinux.lds.S
@@ -57,10 +57,7 @@ SECTIONS
   __alt_instructions_end = .;
  .altinstr_replacement : { *(.altinstr_replacement) }
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
 
 #ifdef CONFIG_BLK_DEV_INITRD
   . = ALIGN(4096);

arch/i386/kernel/vmlinux.lds.S +1 -0

diff -Nurp linux-2.6.21.0/arch/i386/kernel/vmlinux.lds.S linux-2.6.21.1/arch/i386/kernel/vmlinux.lds.S
@@ -180,6 +180,7 @@ SECTIONS
   .data.percpu  : AT(ADDR(.data.percpu) - LOAD_OFFSET) {
 	__per_cpu_start = .;
 	*(.data.percpu)
+	*(.data.percpu.shared_aligned)
 	__per_cpu_end = .;
   }
   . = ALIGN(4096);

arch/ia64/kernel/vmlinux.lds.S +1 -0

diff -Nurp linux-2.6.21.0/arch/ia64/kernel/vmlinux.lds.S linux-2.6.21.1/arch/ia64/kernel/vmlinux.lds.S
@@ -206,6 +206,7 @@ SECTIONS
 	{
 		__per_cpu_start = .;
 		*(.data.percpu)
+		*(.data.percpu.shared_aligned)
 		__per_cpu_end = .;
 	}
   . = __phys_per_cpu_start + PERCPU_PAGE_SIZE;	/* ensure percpu data fits

arch/m32r/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/m32r/kernel/vmlinux.lds.S linux-2.6.21.1/arch/m32r/kernel/vmlinux.lds.S
@@ -110,10 +110,7 @@ SECTIONS
   __initramfs_end = .;
 #endif
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
   . = ALIGN(4096);
   __init_end = .;
   /* freed after init ends here */

arch/mips/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/mips/kernel/vmlinux.lds.S linux-2.6.21.1/arch/mips/kernel/vmlinux.lds.S
@@ -119,10 +119,7 @@ SECTIONS
   .init.ramfs : { *(.init.ramfs) }
   __initramfs_end = .;
 #endif
-  . = ALIGN(_PAGE_SIZE);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(_PAGE_SIZE)
   . = ALIGN(_PAGE_SIZE);
   __init_end = .;
   /* freed after init ends here */

arch/parisc/kernel/vmlinux.lds.S +3 -4

diff -Nurp linux-2.6.21.0/arch/parisc/kernel/vmlinux.lds.S linux-2.6.21.1/arch/parisc/kernel/vmlinux.lds.S
@@ -181,10 +181,9 @@ SECTIONS
   .init.ramfs : { *(.init.ramfs) }
   __initramfs_end = .;
 #endif
-  . = ALIGN(ASM_PAGE_SIZE);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+
+  PERCPU(ASM_PAGE_SIZE)
+
   . = ALIGN(ASM_PAGE_SIZE);
   __init_end = .;
   /* freed after init ends here */

arch/powerpc/kernel/vmlinux.lds.S +1 -0

diff -Nurp linux-2.6.21.0/arch/powerpc/kernel/vmlinux.lds.S linux-2.6.21.1/arch/powerpc/kernel/vmlinux.lds.S
@@ -143,6 +143,7 @@ SECTIONS
 	.data.percpu : {
 		__per_cpu_start = .;
 		*(.data.percpu)
+		*(.data.percpu.shared_aligned)
 		__per_cpu_end = .;
 	}

arch/ppc/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/ppc/kernel/vmlinux.lds.S linux-2.6.21.1/arch/ppc/kernel/vmlinux.lds.S
@@ -130,10 +130,7 @@ SECTIONS
   __ftr_fixup : { *(__ftr_fixup) }
   __stop___ftr_fixup = .;
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
 
 #ifdef CONFIG_BLK_DEV_INITRD
   . = ALIGN(4096);

arch/s390/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/s390/kernel/vmlinux.lds.S linux-2.6.21.1/arch/s390/kernel/vmlinux.lds.S
@@ -107,10 +107,7 @@ SECTIONS
   . = ALIGN(2);
   __initramfs_end = .;
 #endif
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
   . = ALIGN(4096);
   __init_end = .;
   /* freed after init ends here */

arch/sh/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/sh/kernel/vmlinux.lds.S linux-2.6.21.1/arch/sh/kernel/vmlinux.lds.S
@@ -60,10 +60,7 @@ SECTIONS
   . = ALIGN(PAGE_SIZE);
   __nosave_end = .;
 
-  . = ALIGN(PAGE_SIZE);
-  __per_cpu_start = .;
-  .data.percpu : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(PAGE_SIZE)
   .data.cacheline_aligned : { *(.data.cacheline_aligned) }
 
   _edata = .;			/* End of data section */

arch/sh64/kernel/vmlinux.lds.S +4 -1

diff -Nurp linux-2.6.21.0/arch/sh64/kernel/vmlinux.lds.S linux-2.6.21.1/arch/sh64/kernel/vmlinux.lds.S
@@ -87,7 +87,10 @@ SECTIONS
 
   . = ALIGN(PAGE_SIZE);
   __per_cpu_start = .;
-  .data.percpu : C_PHYS(.data.percpu) { *(.data.percpu) }
+  .data.percpu : C_PHYS(.data.percpu) {
+	*(.data.percpu)
+	*(.data.percpu.shared_aligned)
+  }
   __per_cpu_end = . ;
   .data.cacheline_aligned : C_PHYS(.data.cacheline_aligned) { *(.data.cacheline_aligned) }

arch/sparc/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/sparc/kernel/vmlinux.lds.S linux-2.6.21.1/arch/sparc/kernel/vmlinux.lds.S
@@ -65,10 +65,7 @@ SECTIONS
   __initramfs_end = .;
 #endif
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
   . = ALIGN(4096);
   __init_end = .;
   . = ALIGN(32);

arch/sparc64/kernel/vmlinux.lds.S +2 -4

diff -Nurp linux-2.6.21.0/arch/sparc64/kernel/vmlinux.lds.S linux-2.6.21.1/arch/sparc64/kernel/vmlinux.lds.S
@@ -90,10 +90,8 @@ SECTIONS
   __initramfs_end = .;
 #endif
 
-  . = ALIGN(PAGE_SIZE);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(PAGE_SIZE)
+
   . = ALIGN(PAGE_SIZE);
   __init_end = .;
   __bss_start = .;

/* Copies of the original ist values from the tss are only accessed during
* debugging, no special alignment required.

arch/x86_64/kernel/vmlinux.lds.S +2 -4

diff -Nurp linux-2.6.21.0/arch/x86_64/kernel/vmlinux.lds.S linux-2.6.21.1/arch/x86_64/kernel/vmlinux.lds.S
@@ -194,10 +194,8 @@ SECTIONS
   __initramfs_end = .;
 #endif
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : AT(ADDR(.data.percpu) - LOAD_OFFSET) { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
+
   . = ALIGN(4096);
   __init_end = .;

arch/xtensa/kernel/vmlinux.lds.S +1 -4

diff -Nurp linux-2.6.21.0/arch/xtensa/kernel/vmlinux.lds.S linux-2.6.21.1/arch/xtensa/kernel/vmlinux.lds.S
@@ -200,10 +200,7 @@ SECTIONS
   __ftr_fixup : { *(__ftr_fixup) }
   __stop___ftr_fixup = .;
 
-  . = ALIGN(4096);
-  __per_cpu_start = .;
-  .data.percpu  : { *(.data.percpu) }
-  __per_cpu_end = .;
+  PERCPU(4096)
 
 #ifdef CONFIG_BLK_DEV_INITRD
   . = ALIGN(4096);

include/asm-generic/percpu.h +8 -0

diff -Nurp linux-2.6.21.0/include/asm-generic/percpu.h linux-2.6.21.1/include/asm-generic/percpu.h
@@ -14,6 +14,11 @@ extern unsigned long __per_cpu_offset[NR
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 /* var is in discarded region: offset to particular copy we want */
 #define per_cpu(var, cpu) (*({				\
 	extern int simple_identifier_##var(void);	\

@@ -34,6 +39,9 @@ do {								\
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
+
 #define per_cpu(var, cpu)			(*((void)(cpu), &per_cpu__##var))
 #define __get_cpu_var(var)			per_cpu__##var
 #define __raw_get_cpu_var(var)			per_cpu__##var

include/asm-generic/vmlinux.lds.h +8 -0

diff -Nurp linux-2.6.21.0/include/asm-generic/vmlinux.lds.h linux-2.6.21.1/include/asm-generic/vmlinux.lds.h
@@ -245,3 +245,11 @@
   	*(.initcall7.init)						\
   	*(.initcall7s.init)
 
+#define PERCPU(align)							\
+	. = ALIGN(align);						\
+	__per_cpu_start = .;						\
+	.data.percpu  : AT(ADDR(.data.percpu) - LOAD_OFFSET) {		\
+		*(.data.percpu)						\
+		*(.data.percpu.shared_aligned)				\
+	}								\
+	__per_cpu_end = .;

include/asm-i386/percpu.h +5 -0

diff -Nurp linux-2.6.21.0/include/asm-i386/percpu.h linux-2.6.21.1/include/asm-i386/percpu.h
@@ -54,6 +54,11 @@ extern unsigned long __per_cpu_offset[];
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 /* We can use this directly for local CPU (faster). */
 DECLARE_PER_CPU(unsigned long, this_cpu_off);

include/asm-ia64/percpu.h +10 -0

diff -Nurp linux-2.6.21.0/include/asm-ia64/percpu.h linux-2.6.21.1/include/asm-ia64/percpu.h
@@ -29,6 +29,16 @@
 	__attribute__((__section__(".data.percpu")))		\
 	__SMALL_ADDR_AREA __typeof__(type) per_cpu__##name
 
+#ifdef CONFIG_SMP
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)			\
+	__attribute__((__section__(".data.percpu.shared_aligned")))	\
+	__SMALL_ADDR_AREA __typeof__(type) per_cpu__##name		\
+	____cacheline_aligned_in_smp
+#else
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+	DEFINE_PER_CPU(type, name)
+#endif
+
 /*
  * Pretty much a literal copy of asm-generic/percpu.h, except that percpu_modcopy() is an
  * external routine, to avoid include-hell.

include/asm-powerpc/percpu.h +7 -0

diff -Nurp linux-2.6.21.0/include/asm-powerpc/percpu.h linux-2.6.21.1/include/asm-powerpc/percpu.h
@@ -20,6 +20,11 @@
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 /* var is in discarded region: offset to particular copy we want */
 #define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset(cpu)))
 #define __get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))

@@ -40,6 +45,8 @@ extern void setup_per_cpu_areas(void);
 
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
 
 #define per_cpu(var, cpu)			(*((void)(cpu), &per_cpu__##var))
 #define __get_cpu_var(var)			per_cpu__##var

include/asm-s390/percpu.h +7 -0

diff -Nurp linux-2.6.21.0/include/asm-s390/percpu.h linux-2.6.21.1/include/asm-s390/percpu.h
@@ -41,6 +41,11 @@ extern unsigned long __per_cpu_offset[NR
     __attribute__((__section__(".data.percpu"))) \
     __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 #define __get_cpu_var(var) __reloc_hide(var,S390_lowcore.percpu_offset)
 #define __raw_get_cpu_var(var) __reloc_hide(var,S390_lowcore.percpu_offset)
 #define per_cpu(var,cpu) __reloc_hide(var,__per_cpu_offset[cpu])

@@ -59,6 +64,8 @@ do {								\
 
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
 
 #define __get_cpu_var(var) __reloc_hide(var,0)
 #define __raw_get_cpu_var(var) __reloc_hide(var,0)

include/asm-sparc64/percpu.h +7 -0

diff -Nurp linux-2.6.21.0/include/asm-sparc64/percpu.h linux-2.6.21.1/include/asm-sparc64/percpu.h
@@ -18,6 +18,11 @@ extern unsigned long __per_cpu_shift;
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_aligned_in_smp
+
 register unsigned long __local_per_cpu_offset asm("g5");
 
 /* var is in discarded region: offset to particular copy we want */

@@ -38,6 +43,8 @@ do {								\
 #define real_setup_per_cpu_areas()		do { } while (0)
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
 
 #define per_cpu(var, cpu)			(*((void)cpu, &per_cpu__##var))
 #define __get_cpu_var(var)			per_cpu__##var

include/asm-x86_64/percpu.h +7 -0

diff -Nurp linux-2.6.21.0/include/asm-x86_64/percpu.h linux-2.6.21.1/include/asm-x86_64/percpu.h
@@ -20,6 +20,11 @@
 #define DEFINE_PER_CPU(type, name) \
     __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name
 
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)		\
+    __attribute__((__section__(".data.percpu.shared_aligned"))) \
+    __typeof__(type) per_cpu__##name				\
+    ____cacheline_internodealigned_in_smp
+
 /* var is in discarded region: offset to particular copy we want */
 #define per_cpu(var, cpu) (*({				\
 	extern int simple_identifier_##var(void);	\

@@ -46,6 +51,8 @@ extern void setup_per_cpu_areas(void);
 
 #define DEFINE_PER_CPU(type, name) \
     __typeof__(type) per_cpu__##name
+#define DEFINE_PER_CPU_SHARED_ALIGNED(type, name)	\
+    DEFINE_PER_CPU(type, name)
 
 #define per_cpu(var, cpu)			(*((void)(cpu), &per_cpu__##var))
 #define __get_cpu_var(var)			per_cpu__##var