Re: [PATCH v7 24/27] x86: Add swiotlb force off support

From: Yinghai Lu
Date: Mon Dec 24 2012 - 18:55:36 EST


On Mon, Dec 24, 2012 at 3:34 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 12/21/2012 09:11 PM, Yinghai Lu wrote:
>> On Fri, Dec 21, 2012 at 7:25 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>>> On 12/21/2012 07:23 PM, Eric W. Biederman wrote:
>>>>
>>>> In this case YH has been working on the case of loading a kernel
>>>> completely above 4G, and apparently he has also been testing the case of
>>>> running a kernel with no memory below 4G.
>>>>
>>>
>>> It is worth noting that we cannot run with *no* memory below 4G -- it is
>>> not possible to run SMP at least without some memory below the 1M mark.
>>
>> yes need keep 8k or so for trampoline.
>>
>> but kdump only use one CPU.
>>
>
> ... except we have an active request to change that, and the trampoline
> is more like 20K depending on options.

looks like we should not worry that this now.

kdump conf scripts always append some low range under 1M for second kernel.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/