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

[H. Peter Anvin]

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.

	-hpa


--
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/