linux-kernel - Re: [PATCH] Remove initialization of page_table in one_page_table

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Date:	Sat, 18 Jul 2009 16:11:57 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Zhaolei <zhaolei@...fujitsu.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Vegard Nossum <vegard.nossum@...il.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Remove initialization of page_table in
	one_page_table_init()


* Zhaolei <zhaolei@...fujitsu.com> wrote:

> Only judge if (!page_table) when CONFIG_DEBUG_PAGEALLOC or CONFIG_KMEMCHECK
> are defined, then we don't need to set init value for page_table.
>
> Signed-off-by: Zhao Lei <zhaolei@...fujitsu.com>
> ---
> arch/x86/mm/init_32.c |    4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
> index 3cd7711..55da09b 100644
> --- a/arch/x86/mm/init_32.c
> +++ b/arch/x86/mm/init_32.c
> @@ -108,13 +108,13 @@ static pmd_t * __init one_md_table_init(pgd_t *pgd)
> static pte_t * __init one_page_table_init(pmd_t *pmd)
> {
>     if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
> -        pte_t *page_table = NULL;
> +        pte_t *page_table;
>
>         if (after_bootmem) {
> #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
>             page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
> -#endif
>             if (!page_table)
> +#endif
>                 page_table =
>                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);

I think the original code was cleaner - putting an #ifdef straight 
into the middle of a control block is quite fragile.

	Ingo
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