Re: [PATCH 04/13] x86, mm: Revert back good_end setting for 64bit

From: Yinghai Lu
Date: Thu Oct 04 2012 - 17:21:41 EST


On Thu, Oct 4, 2012 at 9:45 AM, Konrad Rzeszutek Wilk
<konrad.wilk@xxxxxxxxxx> wrote:
>> So could use ram under 1M to map that page table at first.
>
> Could or does this patch do it? And why 1MB?

can you or stefano could test attached patch on xen ?

that will map the page table buffer that will be used.

under 1M, still 4k there, so there will be no page table around 512M.

>>
>> so that will make it xen happy ?
>
> The issues that Xen faces are purely due to the fact that they
> must be RO when they are in use. I believe (and without actually
> checking it just to make sure) that it does not matter where
> the page-tables are located. But with the current generic code
> the location is quite linear: it starts with pgt_buf_start and
> goes up to pgt_buf_top. So how would this patch move the location
> of the page-table to be under 1MB?

just page table buf's page table.

Thanks

Yinghai

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