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authorFenghua Yu <fenghua.yu@intel.com>2007-07-19 01:48:12 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-19 10:04:44 -0700
commit5fb7dc37dc16fbc8b80d81318a582201ef7e280d (patch)
tree4d6bb4441ece64380e7186ebadd35ad2f5486f9f /arch
parent3d7e33825d8799115dd2495c9944badd3272a623 (diff)
define new percpu interface for shared data
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 <fenghua.yu@intel.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Christoph Lameter <clameter@sgi.com> Cc: <linux-arch@vger.kernel.org> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/alpha/kernel/vmlinux.lds.S5
-rw-r--r--arch/arm/kernel/vmlinux.lds.S1
-rw-r--r--arch/cris/arch-v32/vmlinux.lds.S5
-rw-r--r--arch/frv/kernel/vmlinux.lds.S5
-rw-r--r--arch/i386/kernel/vmlinux.lds.S1
-rw-r--r--arch/ia64/kernel/vmlinux.lds.S1
-rw-r--r--arch/m32r/kernel/vmlinux.lds.S5
-rw-r--r--arch/mips/kernel/vmlinux.lds.S5
-rw-r--r--arch/parisc/kernel/vmlinux.lds.S7
-rw-r--r--arch/powerpc/kernel/vmlinux.lds.S1
-rw-r--r--arch/ppc/kernel/vmlinux.lds.S5
-rw-r--r--arch/s390/kernel/vmlinux.lds.S5
-rw-r--r--arch/sh/kernel/vmlinux.lds.S5
-rw-r--r--arch/sh64/kernel/vmlinux.lds.S5
-rw-r--r--arch/sparc/kernel/vmlinux.lds.S5
-rw-r--r--arch/sparc64/kernel/vmlinux.lds.S6
-rw-r--r--arch/x86_64/kernel/vmlinux.lds.S6
-rw-r--r--arch/xtensa/kernel/vmlinux.lds.S5
18 files changed, 25 insertions, 53 deletions
diff --git a/arch/alpha/kernel/vmlinux.lds.S b/arch/alpha/kernel/vmlinux.lds.S
index 449e76f118d3..6f4f0378e708 100644
--- a/arch/alpha/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 2b7a8f5d8cf2..5ff5406666b4 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/cris/arch-v32/vmlinux.lds.S b/arch/cris/arch-v32/vmlinux.lds.S
index dfa25e1542b9..651a77f2ccc4 100644
--- a/arch/cris/arch-v32/vmlinux.lds.S
+++ b/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 --git a/arch/frv/kernel/vmlinux.lds.S b/arch/frv/kernel/vmlinux.lds.S
index 481dc1374640..3b71e0c86399 100644
--- a/arch/frv/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S
index 00f1bc47d3a2..4dc44b8007cc 100644
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -181,6 +181,7 @@ SECTIONS
.data.percpu : AT(ADDR(.data.percpu) - LOAD_OFFSET) {
__per_cpu_start = .;
*(.data.percpu)
+ *(.data.percpu.shared_aligned)
__per_cpu_end = .;
}
. = ALIGN(4096);
diff --git a/arch/ia64/kernel/vmlinux.lds.S b/arch/ia64/kernel/vmlinux.lds.S
index 5a65965c8b53..860f251d2fc2 100644
--- a/arch/ia64/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/m32r/kernel/vmlinux.lds.S b/arch/m32r/kernel/vmlinux.lds.S
index 4e2d5b9f0a9a..942a8c7a4417 100644
--- a/arch/m32r/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S
index 9b9992cd562a..bc9bae2a73f4 100644
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/parisc/kernel/vmlinux.lds.S b/arch/parisc/kernel/vmlinux.lds.S
index 4d96ba4b9849..d4e6a93c8d9a 100644
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index ae4acd84143d..39fda6e6aa47 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -144,6 +144,7 @@ SECTIONS
.data.percpu : {
__per_cpu_start = .;
*(.data.percpu)
+ *(.data.percpu.shared_aligned)
__per_cpu_end = .;
}
diff --git a/arch/ppc/kernel/vmlinux.lds.S b/arch/ppc/kernel/vmlinux.lds.S
index 19db8746ff14..c0aac3ff9e91 100644
--- a/arch/ppc/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/s390/kernel/vmlinux.lds.S b/arch/s390/kernel/vmlinux.lds.S
index 7158a804a5e4..61ffd50fac40 100644
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/sh/kernel/vmlinux.lds.S b/arch/sh/kernel/vmlinux.lds.S
index 0696402f446a..5ba216180b30 100644
--- a/arch/sh/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/sh64/kernel/vmlinux.lds.S b/arch/sh64/kernel/vmlinux.lds.S
index 02aea86c5907..8ac9c7c5f848 100644
--- a/arch/sh64/kernel/vmlinux.lds.S
+++ b/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) }
diff --git a/arch/sparc/kernel/vmlinux.lds.S b/arch/sparc/kernel/vmlinux.lds.S
index f75a1b822789..47583887abc6 100644
--- a/arch/sparc/kernel/vmlinux.lds.S
+++ b/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 --git a/arch/sparc64/kernel/vmlinux.lds.S b/arch/sparc64/kernel/vmlinux.lds.S
index 3ad10f3027e4..481861764deb 100644
--- a/arch/sparc64/kernel/vmlinux.lds.S
+++ b/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 = .;
diff --git a/arch/x86_64/kernel/vmlinux.lds.S b/arch/x86_64/kernel/vmlinux.lds.S
index dbccfda8364f..22590690a8a0 100644
--- a/arch/x86_64/kernel/vmlinux.lds.S
+++ b/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 = .;
diff --git a/arch/xtensa/kernel/vmlinux.lds.S b/arch/xtensa/kernel/vmlinux.lds.S
index b0582c3c5f8d..3e31512109f9 100644
--- a/arch/xtensa/kernel/vmlinux.lds.S
+++ b/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 */

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