* [PATCH 2/2] Allow percpu variables to be page-aligned
@ 2007-04-10 17:09 Jeremy Fitzhardinge
2007-04-10 22:22 ` Eric W. Biederman
0 siblings, 1 reply; 3+ messages in thread
From: Jeremy Fitzhardinge @ 2007-04-10 17:09 UTC (permalink / raw)
To: Andrew Morton
Cc: Andi Kleen, Linux Kernel Mailing List, Eric W. Biederman,
Rusty Russell
Let's allow page-alignment in general for per-cpu data (wanted by Xen, and
Ingo suggested KVM as well).
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@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
arch/alpha/kernel/vmlinux.lds.S | 2 +-
arch/arm/kernel/vmlinux.lds.S | 2 +-
arch/cris/arch-v32/vmlinux.lds.S | 1 +
arch/frv/kernel/vmlinux.lds.S | 1 +
arch/i386/kernel/vmlinux.lds.S | 2 +-
arch/m32r/kernel/vmlinux.lds.S | 2 +-
arch/mips/kernel/vmlinux.lds.S | 2 +-
arch/parisc/kernel/vmlinux.lds.S | 2 +-
arch/powerpc/kernel/setup_64.c | 4 ++--
arch/powerpc/kernel/vmlinux.lds.S | 6 +-----
arch/ppc/kernel/vmlinux.lds.S | 2 +-
arch/s390/kernel/vmlinux.lds.S | 2 +-
arch/sh/kernel/vmlinux.lds.S | 2 +-
arch/sh64/kernel/vmlinux.lds.S | 2 +-
arch/sparc/kernel/vmlinux.lds.S | 2 +-
arch/sparc64/kernel/smp.c | 6 +++---
arch/x86_64/kernel/setup64.c | 4 ++--
arch/x86_64/kernel/vmlinux.lds.S | 2 +-
arch/xtensa/kernel/vmlinux.lds.S | 2 +-
init/main.c | 4 ++--
kernel/module.c | 8 ++++----
21 files changed, 29 insertions(+), 31 deletions(-)
===================================================================
--- a/arch/alpha/kernel/vmlinux.lds.S
+++ b/arch/alpha/kernel/vmlinux.lds.S
@@ -69,7 +69,7 @@ SECTIONS
. = ALIGN(8);
SECURITY_INIT
- . = ALIGN(64);
+ . = ALIGN(8192);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
===================================================================
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -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 = .;
===================================================================
--- a/arch/cris/arch-v32/vmlinux.lds.S
+++ b/arch/cris/arch-v32/vmlinux.lds.S
@@ -91,6 +91,7 @@ SECTIONS
}
SECURITY_INIT
+ . = ALIGN (8192);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
===================================================================
--- a/arch/frv/kernel/vmlinux.lds.S
+++ b/arch/frv/kernel/vmlinux.lds.S
@@ -57,6 +57,7 @@ SECTIONS
__alt_instructions_end = .;
.altinstr_replacement : { *(.altinstr_replacement) }
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
===================================================================
--- a/arch/i386/kernel/vmlinux.lds.S
+++ b/arch/i386/kernel/vmlinux.lds.S
@@ -194,7 +194,7 @@ SECTIONS
__initramfs_end = .;
}
#endif
- . = ALIGN(L1_CACHE_BYTES);
+ . = ALIGN(4096);
.data.percpu : AT(ADDR(.data.percpu) - LOAD_OFFSET) {
__per_cpu_start = .;
*(.data.percpu)
===================================================================
--- a/arch/m32r/kernel/vmlinux.lds.S
+++ b/arch/m32r/kernel/vmlinux.lds.S
@@ -110,7 +110,7 @@ SECTIONS
__initramfs_end = .;
#endif
- . = ALIGN(32);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
===================================================================
--- a/arch/mips/kernel/vmlinux.lds.S
+++ b/arch/mips/kernel/vmlinux.lds.S
@@ -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 = .;
===================================================================
--- a/arch/parisc/kernel/vmlinux.lds.S
+++ b/arch/parisc/kernel/vmlinux.lds.S
@@ -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 = .;
===================================================================
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -583,14 +583,14 @@ void __init setup_per_cpu_areas(void)
char *ptr;
/* 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
for_each_possible_cpu(i) {
- ptr = alloc_bootmem_node(NODE_DATA(cpu_to_node(i)), size);
+ ptr = alloc_bootmem_pages_node(NODE_DATA(cpu_to_node(i)), size);
if (!ptr)
panic("Cannot allocate cpu data for CPU %d\n", i);
===================================================================
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -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)
===================================================================
--- a/arch/ppc/kernel/vmlinux.lds.S
+++ b/arch/ppc/kernel/vmlinux.lds.S
@@ -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 = .;
===================================================================
--- a/arch/s390/kernel/vmlinux.lds.S
+++ b/arch/s390/kernel/vmlinux.lds.S
@@ -99,7 +99,7 @@ SECTIONS
. = ALIGN(2);
__initramfs_end = .;
#endif
- . = ALIGN(256);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
===================================================================
--- a/arch/sh/kernel/vmlinux.lds.S
+++ b/arch/sh/kernel/vmlinux.lds.S
@@ -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 = .;
===================================================================
--- a/arch/sh64/kernel/vmlinux.lds.S
+++ b/arch/sh64/kernel/vmlinux.lds.S
@@ -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 = . ;
===================================================================
--- a/arch/sparc/kernel/vmlinux.lds.S
+++ b/arch/sparc/kernel/vmlinux.lds.S
@@ -65,7 +65,7 @@ SECTIONS
__initramfs_end = .;
#endif
- . = ALIGN(32);
+ . = ALIGN(4096);
__per_cpu_start = .;
.data.percpu : { *(.data.percpu) }
__per_cpu_end = .;
===================================================================
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -1449,11 +1449,11 @@ void __init setup_per_cpu_areas(void)
/* Copy section for each CPU (we discard the original) */
goal = PERCPU_ENOUGH_ROOM;
- __per_cpu_shift = 0;
- for (size = 1UL; size < goal; size <<= 1UL)
+ __per_cpu_shift = PAGE_SHIFT;
+ for (size = PAGE_SIZE; size < goal; size <<= 1UL)
__per_cpu_shift++;
- ptr = alloc_bootmem(size * NR_CPUS);
+ ptr = alloc_bootmem_pages(size * NR_CPUS);
__per_cpu_base = ptr - __per_cpu_start;
===================================================================
--- a/arch/x86_64/kernel/setup64.c
+++ b/arch/x86_64/kernel/setup64.c
@@ -103,9 +103,9 @@ void __init setup_per_cpu_areas(void)
if (!NODE_DATA(cpu_to_node(i))) {
printk("cpu with no node %d, num_online_nodes %d\n",
i, num_online_nodes());
- ptr = alloc_bootmem(size);
+ ptr = alloc_bootmem_pages(size);
} else {
- ptr = alloc_bootmem_node(NODE_DATA(cpu_to_node(i)), size);
+ ptr = alloc_bootmem_pages_node(NODE_DATA(cpu_to_node(i)), size);
}
if (!ptr)
panic("Cannot allocate cpu data for CPU %d\n", i);
===================================================================
--- a/arch/x86_64/kernel/vmlinux.lds.S
+++ b/arch/x86_64/kernel/vmlinux.lds.S
@@ -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 = .;
===================================================================
--- a/arch/xtensa/kernel/vmlinux.lds.S
+++ b/arch/xtensa/kernel/vmlinux.lds.S
@@ -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 = .;
===================================================================
--- a/init/main.c
+++ b/init/main.c
@@ -370,8 +370,8 @@ static void __init setup_per_cpu_areas(v
/* Copy section for each CPU (we discard the original) */
- size = ALIGN(PERCPU_ENOUGH_ROOM, SMP_CACHE_BYTES);
- ptr = alloc_bootmem(size * nr_possible_cpus);
+ size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
+ ptr = alloc_bootmem_pages(size * nr_possible_cpus);
for_each_possible_cpu(i) {
__per_cpu_offset[i] = ptr - __per_cpu_start;
===================================================================
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -346,10 +346,10 @@ 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;
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2] Allow percpu variables to be page-aligned
2007-04-10 17:09 [PATCH 2/2] Allow percpu variables to be page-aligned Jeremy Fitzhardinge
@ 2007-04-10 22:22 ` Eric W. Biederman
2007-04-10 22:49 ` Jeremy Fitzhardinge
0 siblings, 1 reply; 3+ messages in thread
From: Eric W. Biederman @ 2007-04-10 22:22 UTC (permalink / raw)
To: Jeremy Fitzhardinge
Cc: Andrew Morton, Andi Kleen, Linux Kernel Mailing List,
Rusty Russell
Jeremy Fitzhardinge <jeremy@goop.org> writes:
> Let's allow page-alignment in general for per-cpu data (wanted by Xen, and
> Ingo suggested KVM as well).
>
> 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.
The second paragraph of the comment is dated. You are not changing the per-cpu
memory size at all now.
The code itself looks sane.
Although we should probably fail the module load if the requested alignment
is to great, but that is just picking nits, and is no worse than what we
do today.
Eric
> ===================================================================
> --- a/kernel/module.c
> +++ b/kernel/module.c
> @@ -346,10 +346,10 @@ 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;
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH 2/2] Allow percpu variables to be page-aligned
2007-04-10 22:22 ` Eric W. Biederman
@ 2007-04-10 22:49 ` Jeremy Fitzhardinge
0 siblings, 0 replies; 3+ messages in thread
From: Jeremy Fitzhardinge @ 2007-04-10 22:49 UTC (permalink / raw)
To: Eric W. Biederman
Cc: Andrew Morton, Andi Kleen, Linux Kernel Mailing List,
Rusty Russell
Eric W. Biederman wrote:
> Jeremy Fitzhardinge <jeremy@goop.org> writes:
>
>
>> Let's allow page-alignment in general for per-cpu data (wanted by Xen, and
>> Ingo suggested KVM as well).
>>
>> 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.
>>
>
> The second paragraph of the comment is dated. You are not changing the per-cpu
> memory size at all now.
>
Yup.
> Although we should probably fail the module load if the requested alignment
> is to great, but that is just picking nits, and is no worse than what we
> do today.
>
Yes. And we barely support a module's use of page-aligned data, since
it would potentially chew through the percpu space very quickly.
J
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2007-04-10 22:49 UTC | newest]
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2007-04-10 22:22 ` Eric W. Biederman
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