[PATCH 6/8] Allow per-cpu variables to be page-aligned

From: Rusty Russell
Date: Tue Mar 06 2007 - 08:01:47 EST

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Xen wants page-aligned GDT (and PDA must not cross a page-boundary,
but that doesn't happen at the moment since it's so close to start of
page). Let's allow page-alignment in general for per-cpu data.

Because larger alignments can use more room, we increase the max
per-cpu memory to 64k rather than 32k: it's getting a little tight.

Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>

diff -r 213b1ec27001 arch/alpha/kernel/vmlinux.lds.S
--- a/arch/alpha/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/alpha/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -69,7 +69,7 @@ SECTIONS
. = ALIGN(8);
SECURITY_INIT

- . = ALIGN(64);
+ . = ALIGN(8192);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/arm/kernel/vmlinux.lds.S
--- a/arch/arm/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/arm/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -59,7 +59,7 @@ SECTIONS
usr/built-in.o(.init.ramfs)
__initramfs_end = .;
#endif
- . = ALIGN(64);
+ . = ALIGN(4096);
__per_cpu_start = .;
*(.data.percpu)
__per_cpu_end = .;
diff -r 213b1ec27001 arch/cris/arch-v32/vmlinux.lds.S
--- a/arch/cris/arch-v32/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/cris/arch-v32/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -91,6 +91,7 @@ SECTIONS
}
SECURITY_INIT

+ . = ALIGN (8192);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/frv/kernel/vmlinux.lds.S
--- a/arch/frv/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/frv/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -57,6 +57,7 @@ SECTIONS
__alt_instructions_end = .;
.altinstr_replacement : { *(.altinstr_replacement) }

+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/i386/kernel/vmlinux.lds.S
--- a/arch/i386/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/i386/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -196,7 +196,7 @@ SECTIONS
__initramfs_end = .;
}
#endif
- . = ALIGN(L1_CACHE_BYTES);
+ . = ALIGN(4096);
.data.percpu : AT(ADDR(.data.percpu) - LOAD_OFFSET) {
__per_cpu_start = .;
*(.data.percpu)
diff -r 213b1ec27001 arch/m32r/kernel/vmlinux.lds.S
--- a/arch/m32r/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/m32r/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -110,7 +110,7 @@ SECTIONS
__initramfs_end = .;
#endif

- . = ALIGN(32);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/mips/kernel/vmlinux.lds.S
--- a/arch/mips/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/mips/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -119,7 +119,7 @@ SECTIONS
.init.ramfs : { *(.init.ramfs) }
__initramfs_end = .;
#endif
- . = ALIGN(32);
+ . = ALIGN(_PAGE_SIZE);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/parisc/kernel/vmlinux.lds.S
--- a/arch/parisc/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/parisc/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -181,7 +181,7 @@ SECTIONS
.init.ramfs : { *(.init.ramfs) }
__initramfs_end = .;
#endif
- . = ALIGN(32);
+ . = ALIGN(ASM_PAGE_SIZE);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/powerpc/kernel/vmlinux.lds.S
--- a/arch/powerpc/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/powerpc/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -139,11 +139,7 @@ SECTIONS
__initramfs_end = .;
}
#endif
-#ifdef CONFIG_PPC32
- . = ALIGN(32);
-#else
- . = ALIGN(128);
-#endif
+ . = ALIGN(PAGE_SIZE);
.data.percpu : {
__per_cpu_start = .;
*(.data.percpu)
diff -r 213b1ec27001 arch/ppc/kernel/vmlinux.lds.S
--- a/arch/ppc/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/ppc/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -130,7 +130,7 @@ SECTIONS
__ftr_fixup : { *(__ftr_fixup) }
__stop___ftr_fixup = .;

- . = ALIGN(32);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/s390/kernel/vmlinux.lds.S
--- a/arch/s390/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/s390/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -99,7 +99,7 @@ SECTIONS
. = ALIGN(2);
__initramfs_end = .;
#endif
- . = ALIGN(256);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/sh/kernel/vmlinux.lds.S
--- a/arch/sh/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/sh/kernel/vmlinux.lds.S Tue Mar 06 19:02:25 2007 +1100
@@ -54,7 +54,7 @@ SECTIONS
. = ALIGN(PAGE_SIZE);
.data.page_aligned : { *(.data.page_aligned) }

- . = ALIGN(L1_CACHE_BYTES);
+ . = ALIGN(PAGE_SIZE);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/sh64/kernel/vmlinux.lds.S
--- a/arch/sh64/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/sh64/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -85,7 +85,7 @@ SECTIONS
. = ALIGN(PAGE_SIZE);
.data.page_aligned : C_PHYS(.data.page_aligned) { *(.data.page_aligned) }

- . = ALIGN(L1_CACHE_BYTES);
+ . = ALIGN(PAGE_SIZE);
__per_cpu_start = .;
.data.percpu : C_PHYS(.data.percpu) { *(.data.percpu) }
__per_cpu_end = . ;
diff -r 213b1ec27001 arch/sparc/kernel/vmlinux.lds.S
--- a/arch/sparc/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/sparc/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -65,7 +65,7 @@ SECTIONS
__initramfs_end = .;
#endif

- . = ALIGN(32);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/x86_64/kernel/vmlinux.lds.S
--- a/arch/x86_64/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/x86_64/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -194,7 +194,7 @@ SECTIONS
__initramfs_end = .;
#endif

- . = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : AT(ADDR(.data.percpu) - LOAD_OFFSET) { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 arch/xtensa/kernel/vmlinux.lds.S
--- a/arch/xtensa/kernel/vmlinux.lds.S Tue Mar 06 19:01:59 2007 +1100
+++ b/arch/xtensa/kernel/vmlinux.lds.S Tue Mar 06 19:02:03 2007 +1100
@@ -198,7 +198,7 @@ SECTIONS
__ftr_fixup : { *(__ftr_fixup) }
__stop___ftr_fixup = .;

- . = ALIGN(32);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
diff -r 213b1ec27001 include/linux/percpu.h
--- a/include/linux/percpu.h Tue Mar 06 19:01:59 2007 +1100
+++ b/include/linux/percpu.h Tue Mar 06 23:32:35 2007 +1100
@@ -11,7 +11,7 @@

/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
#ifndef PERCPU_ENOUGH_ROOM
-#define PERCPU_ENOUGH_ROOM 32768
+#define PERCPU_ENOUGH_ROOM 65536
#endif

/*
diff -r 213b1ec27001 init/main.c
--- a/init/main.c Tue Mar 06 19:01:59 2007 +1100
+++ b/init/main.c Tue Mar 06 19:02:03 2007 +1100
@@ -368,12 +368,12 @@ static void __init setup_per_cpu_areas(v
unsigned long nr_possible_cpus = num_possible_cpus();

/* Copy section for each CPU (we discard the original) */
- size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
+ size = ALIGN(__per_cpu_end - __per_cpu_start, PAGE_SIZE);
#ifdef CONFIG_MODULES
if (size < PERCPU_ENOUGH_ROOM)
size = PERCPU_ENOUGH_ROOM;
#endif
- ptr = alloc_bootmem(size * nr_possible_cpus);
+ ptr = alloc_bootmem_pages(size * nr_possible_cpus);

for_each_possible_cpu(i) {
__per_cpu_offset[i] = ptr - __per_cpu_start;
diff -r 213b1ec27001 kernel/module.c
--- a/kernel/module.c Tue Mar 06 19:01:59 2007 +1100
+++ b/kernel/module.c Tue Mar 06 19:02:03 2007 +1100
@@ -544,10 +544,10 @@ static void *percpu_modalloc(unsigned lo
unsigned int i;
void *ptr;

- if (align > SMP_CACHE_BYTES) {
- printk(KERN_WARNING "%s: per-cpu alignment %li > %i\n",
- name, align, SMP_CACHE_BYTES);
- align = SMP_CACHE_BYTES;
+ if (align > PAGE_SIZE) {
+ printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
+ name, align, PAGE_SIZE);
+ align = PAGE_SIZE;
}

ptr = __per_cpu_start;
@@ -628,7 +628,7 @@ static int percpu_modinit(void)
pcpu_size = kmalloc(sizeof(pcpu_size[0]) * pcpu_num_allocated,
GFP_KERNEL);
/* Static in-kernel percpu data (used). */
- pcpu_size[0] = -ALIGN(__per_cpu_end-__per_cpu_start, SMP_CACHE_BYTES);
+ pcpu_size[0] = -ALIGN(__per_cpu_end-__per_cpu_start, PAGE_SIZE);
/* Free room. */
pcpu_size[1] = PERCPU_ENOUGH_ROOM + pcpu_size[0];
if (pcpu_size[1] < 0) {

-
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Next message: Rusty Russell: "[PATCH 7/8] Page-align the GDT"
Previous message: Rusty Russell: "[PATCH 5/8] Cleanup GDT access"
In reply to: Rusty Russell: "[PATCH 5/8] Cleanup GDT access"
Next in thread: Rusty Russell: "[PATCH 7/8] Page-align the GDT"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]