Re: [PATCH] mm: skip if required_kernelcore is larger than totalpages

From: Yasuaki Ishimatsu
Date: Fri Oct 09 2015 - 11:41:22 EST



On Thu, 8 Oct 2015 10:21:05 +0800
Xishi Qiu <qiuxishi@xxxxxxxxxx> wrote:

> If kernelcore was not specified, or the kernelcore size is zero
> (required_movablecore >= totalpages), or the kernelcore size is larger

Why does required_movablecore become larger than totalpages, when the
kernelcore size is zero? I read the code but I could not find that you
mention.

Thanks,
Yasuaki Ishimatsu

> than totalpages, there is no ZONE_MOVABLE. We should fill the zone
> with both kernel memory and movable memory.
>
> Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
> ---
> mm/page_alloc.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index af3c9bd..6a6da0d 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5674,8 +5674,11 @@ static void __init find_zone_movable_pfns_for_nodes(void)
> required_kernelcore = max(required_kernelcore, corepages);
> }
>
> - /* If kernelcore was not specified, there is no ZONE_MOVABLE */
> - if (!required_kernelcore)
> + /*
> + * If kernelcore was not specified or kernelcore size is larger
> + * than totalpages, there is no ZONE_MOVABLE.
> + */
> + if (!required_kernelcore || required_kernelcore >= totalpages)
> goto out;
>
> /* usable_startpfn is the lowest possible pfn ZONE_MOVABLE can be at */
> --
> 2.0.0
>
>
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