Re: [patch 3/3]use new macros for x86 percpu readmostly section

From: Andrew Morton
Date: Thu Dec 09 2010 - 17:32:40 EST


On Thu, 02 Dec 2010 10:02:30 +0800
Shaohua Li <shaohua.li@xxxxxxxxx> wrote:

> Use the new macros to correctly align percpu readmostly data.
>
> Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
> ---
> arch/x86/kernel/vmlinux.lds.S | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> Index: linux/arch/x86/kernel/vmlinux.lds.S
> ===================================================================
> --- linux.orig/arch/x86/kernel/vmlinux.lds.S 2010-12-02 09:48:44.000000000 +0800
> +++ linux/arch/x86/kernel/vmlinux.lds.S 2010-12-02 09:54:24.000000000 +0800
> @@ -226,7 +226,7 @@ SECTIONS
> * output PHDR, so the next output section - .init.text - should
> * start another segment - init.
> */
> - PERCPU_VADDR(0, :percpu)
> + PERCPU_VADDR_CACHEALIGNED(0, :percpu, INTERNODE_CACHE_BYTES)
> #endif
>
> INIT_TEXT_SECTION(PAGE_SIZE)
> @@ -301,7 +301,7 @@ SECTIONS
> }
>
> #if !defined(CONFIG_X86_64) || !defined(CONFIG_SMP)
> - PERCPU(THREAD_SIZE)
> + PERCPU_CACHEALIGNED(THREAD_SIZE, INTERNODE_CACHE_BYTES)
> #endif
>
> . = ALIGN(PAGE_SIZE);
>

So what is the situation now with all other architectures? Should they
be changed to correctly align their read-mostly percpu areas?

If so, what should the arch maintainers do to achieve this?
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