Subject: Re: [PATCH 1/5 V2] Align stack boundaries based on personality

From: Dave Hansen <[email-masked]>
Date: Mon, 28 Jul 2008 13:09:53 -0700

On Mon, 2008-07-28 at 12:17 -0700, Eric Munson wrote:
> 
> +static unsigned long personality_page_align(unsigned long addr)
> +{
> +       if (current->personality & HUGETLB_STACK)
> +#ifdef CONFIG_STACK_GROWSUP
> +               return HPAGE_ALIGN(addr);
> +#else
> +               return addr & HPAGE_MASK;
> +#endif
> +
> +       return PAGE_ALIGN(addr);
> +}
...
> -       stack_top = PAGE_ALIGN(stack_top);
> +       stack_top = personality_page_align(stack_top);

Just out of curiosity, why doesn't the existing small-page case seem to
care about the stack growing up/down?  Why do you need to care in the
large page case?

-- Dave