Re: [PATCH RFC 1/2] [x86] Modify comments and clean up code.

From: Borislav Petkov
Date: Sun Oct 14 2012 - 06:49:47 EST


On Thu, Oct 11, 2012 at 08:28:44PM +0800, ling.ma@xxxxxxxxx wrote:
> From: Ma Ling <ling.ma@xxxxxxxxx>
>
> Modern CPU use fast-string instruction to accelerate copy performance,
> by combining data into 128bit, so we modify comments and code style.
>
> Signed-off-by: Ma Ling <ling.ma@xxxxxxxxx>
>
> ---
> arch/x86/lib/copy_page_64.S | 119 +++++++++++++++++++++----------------------
> 1 files changed, 59 insertions(+), 60 deletions(-)
>
> diff --git a/arch/x86/lib/copy_page_64.S b/arch/x86/lib/copy_page_64.S
> index 6b34d04..3da5527 100644
> --- a/arch/x86/lib/copy_page_64.S
> +++ b/arch/x86/lib/copy_page_64.S
> @@ -5,91 +5,90 @@
> #include <asm/alternative-asm.h>
>
> ALIGN
> -copy_page_c:
> +copy_page_rep:
> CFI_STARTPROC
> - movl $4096/8,%ecx
> - rep movsq
> + movl $4096/8, %ecx
> + rep movsq
> ret
> CFI_ENDPROC
> -ENDPROC(copy_page_c)
> +ENDPROC(copy_page_rep)
>
> -/* Don't use streaming store because it's better when the target
> - ends up in cache. */
> -
> -/* Could vary the prefetch distance based on SMP/UP */
> +/*
> + Don't use streaming copy unless cpu indicate X86_FEATURE_REP_GOOD
> + Could vary the prefetch distance based on SMP/UP
> +*/

Kernel comment style formatting is:

/*
* <something not trivial to see worth adding comment for>
* <optional second line of that statement>
*/

>
> ENTRY(copy_page)
> CFI_STARTPROC
> - subq $2*8,%rsp
> + subq $2*8, %rsp
> CFI_ADJUST_CFA_OFFSET 2*8
> - movq %rbx,(%rsp)
> + movq %rbx, (%rsp)
> CFI_REL_OFFSET rbx, 0
> - movq %r12,1*8(%rsp)
> + movq %r12, 1*8(%rsp)
> CFI_REL_OFFSET r12, 1*8
>
> - movl $(4096/64)-5,%ecx
> + movl $(4096/64)-5, %ecx
> .p2align 4
> .Loop64:
> - dec %rcx
> + dec %rcx

Applying: Modify comments and clean up code.
/home/boris/kernel/linux-2.6/.git/rebase-apply/patch:51: space before tab in indent.
dec %rcx
warning: 1 line adds whitespace errors.

>
> - movq (%rsi), %rax
> - movq 8 (%rsi), %rbx
> - movq 16 (%rsi), %rdx
> - movq 24 (%rsi), %r8
> - movq 32 (%rsi), %r9
> - movq 40 (%rsi), %r10
> - movq 48 (%rsi), %r11
> - movq 56 (%rsi), %r12
> + movq 0x8*0(%rsi), %rax
> + movq 0x8*1(%rsi), %rbx
> + movq 0x8*2(%rsi), %rdx
> + movq 0x8*3(%rsi), %r8
> + movq 0x8*4(%rsi), %r9
> + movq 0x8*5(%rsi), %r10
> + movq 0x8*6(%rsi), %r11
> + movq 0x8*7(%rsi), %r12

[ â ]

--
Regards/Gruss,
Boris.
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