Re: [PATCH - resend] Memory-Hotplug: Fix the bug on interface/dev/mem for 64-bit kernel(v1)

From: KAMEZAWA Hiroyuki
Date: Mon Jan 11 2010 - 21:42:24 EST


On Tue, 12 Jan 2010 10:33:08 +0800
Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:

> Sure, here it is :)
> ---
> x86: use the generic page_is_ram()
>
> The generic resource based page_is_ram() works better with memory
> hotplug/hotremove. So switch the x86 e820map based code to it.
>
> CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
> CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Signed-off-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>

Ack.


> +#ifdef CONFIG_X86
> + /*
> + * A special case is the first 4Kb of memory;
> + * This is a BIOS owned area, not kernel ram, but generally
> + * not listed as such in the E820 table.
> + */
> + if (pfn == 0)
> + return 0;
> +
> + /*
> + * Second special case: Some BIOSen report the PC BIOS
> + * area (640->1Mb) as ram even though it is not.
> + */
> + if (pfn >= (BIOS_BEGIN >> PAGE_SHIFT) &&
> + pfn < (BIOS_END >> PAGE_SHIFT))
> + return 0;
> +#endif

I'm glad if this part is sorted out in clean way ;)

Thanks,
-Kame

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