The patch titled
Define new percpu interface for shared data
has been removed from the -mm tree. Its filename was
define-new-percpu-interface-for-shared-data.patch
This patch was dropped because it had testing failures
------------------------------------------------------
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.
Depending on how linker places percpu data, the patches could
increase or decrease percpu section size. Data from 2.6.21-rc7-mm2:
On x86 SMP, the section size is increased from 0x7768 to 0x790c.
1.3% increase.
On X86-64 SMP, the size is decreased from 0x72d0 to 0x6540.
11.8% decrease.
On X86-64 VSMP, the size is increased from 0x72d0 to 0x8340.
14.3% increase.
On IA64 SMP, the size is decreased from 0x8370 to 0x7fc0.
2.8% decrease.
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]>
Acked-by: Ravikiran Thirumalai <[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(-)
diff -puN
arch/alpha/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/alpha/kernel/vmlinux.lds.S
---
a/arch/alpha/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 = .;
diff -puN
arch/arm/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/arm/kernel/vmlinux.lds.S
--- a/arch/arm/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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;
diff -puN
arch/cris/arch-v32/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/cris/arch-v32/vmlinux.lds.S
---
a/arch/cris/arch-v32/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 : {
diff -puN
arch/frv/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/frv/kernel/vmlinux.lds.S
--- a/arch/frv/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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);
diff -puN
arch/i386/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/i386/kernel/vmlinux.lds.S
--- a/arch/i386/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 */
diff -puN
arch/ia64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/ia64/kernel/vmlinux.lds.S
--- a/arch/ia64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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
diff -puN
arch/m32r/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/m32r/kernel/vmlinux.lds.S
--- a/arch/m32r/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 */
diff -puN
arch/mips/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/mips/kernel/vmlinux.lds.S
--- a/arch/mips/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 */
diff -puN
arch/parisc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/parisc/kernel/vmlinux.lds.S
---
a/arch/parisc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 */
diff -puN
arch/powerpc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/powerpc/kernel/vmlinux.lds.S
---
a/arch/powerpc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 : {
diff -puN
arch/ppc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/ppc/kernel/vmlinux.lds.S
--- a/arch/ppc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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);
diff -puN
arch/s390/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/s390/kernel/vmlinux.lds.S
--- a/arch/s390/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 */
diff -puN
arch/sh/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/sh/kernel/vmlinux.lds.S
--- a/arch/sh/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 */
diff -puN
arch/sh64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/sh64/kernel/vmlinux.lds.S
--- a/arch/sh64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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 */
diff -puN
arch/sparc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/sparc/kernel/vmlinux.lds.S
---
a/arch/sparc/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/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);
diff -puN
arch/sparc64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/sparc64/kernel/vmlinux.lds.S
---
a/arch/sparc64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/arch/sparc64/kernel/vmlinux.lds.S
@@ -90,10 +90,7 @@ 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 = .;
diff -puN
arch/x86_64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/x86_64/kernel/vmlinux.lds.S
---
a/arch/x86_64/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/arch/x86_64/kernel/vmlinux.lds.S
@@ -210,10 +210,8 @@ 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 = .;
diff -puN
arch/xtensa/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
arch/xtensa/kernel/vmlinux.lds.S
---
a/arch/xtensa/kernel/vmlinux.lds.S~define-new-percpu-interface-for-shared-data
+++ a/arch/xtensa/kernel/vmlinux.lds.S
@@ -190,10 +190,7 @@ SECTIONS
__initramfs_end = .;
#endif
- . = ALIGN(4096);
- __per_cpu_start = .;
- .data.percpu : { *(.data.percpu) }
- __per_cpu_end = .;
+ PERCPU(4096)
/* We need this dummy segment here */
diff -puN
include/asm-generic/percpu.h~define-new-percpu-interface-for-shared-data
include/asm-generic/percpu.h
--- a/include/asm-generic/percpu.h~define-new-percpu-interface-for-shared-data
+++ a/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
diff -puN
include/asm-generic/vmlinux.lds.h~define-new-percpu-interface-for-shared-data
include/asm-generic/vmlinux.lds.h
---
a/include/asm-generic/vmlinux.lds.h~define-new-percpu-interface-for-shared-data
+++ a/include/asm-generic/vmlinux.lds.h
@@ -267,3 +267,11 @@
*(.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 = .;
diff -puN include/asm-i386/percpu.h~define-new-percpu-interface-for-shared-data
include/asm-i386/percpu.h
--- a/include/asm-i386/percpu.h~define-new-percpu-interface-for-shared-data
+++ a/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);
diff -puN include/asm-ia64/percpu.h~define-new-percpu-interface-for-shared-data
include/asm-ia64/percpu.h
--- a/include/asm-ia64/percpu.h~define-new-percpu-interface-for-shared-data
+++ a/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.
diff -puN
include/asm-powerpc/percpu.h~define-new-percpu-interface-for-shared-data
include/asm-powerpc/percpu.h
--- a/include/asm-powerpc/percpu.h~define-new-percpu-interface-for-shared-data
+++ a/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
diff -puN include/asm-s390/percpu.h~define-new-percpu-interface-for-shared-data
include/asm-s390/percpu.h
--- a/include/asm-s390/percpu.h~define-new-percpu-interface-for-shared-data
+++ a/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)
diff -puN
include/asm-sparc64/percpu.h~define-new-percpu-interface-for-shared-data
include/asm-sparc64/percpu.h
--- a/include/asm-sparc64/percpu.h~define-new-percpu-interface-for-shared-data
+++ a/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
diff -puN
include/asm-x86_64/percpu.h~define-new-percpu-interface-for-shared-data
include/asm-x86_64/percpu.h
--- a/include/asm-x86_64/percpu.h~define-new-percpu-interface-for-shared-data
+++ a/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
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