Re: [PATCH] kexec: use Crash kernel for Crash kernel low

From: H. Peter Anvin
Date: Mon Apr 01 2013 - 18:02:25 EST


On 04/01/2013 02:10 PM, Yinghai Lu wrote:
> On Mon, Apr 1, 2013 at 1:47 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>> On 04/01/2013 12:26 PM, Vivek Goyal wrote:
>>
>>> crashkernel=<size>,<option>,<option>.. and crashkernel=800M,high sound
>>> good to me.
>>>
>>> So atleast for 3.9 kernel, shall we hide new semantics behind
>>> crashkernel=XM,high and by default crashkernel=XM tries to emulate
>>> crashkernel=XM,low to retain backward compatibility?
>>
>> Yes, I suspect so.
>
> current we have:
> 1. crashkernel=XM
> 2. crashkernel=XM crashkernel_low=YM
>
> so you want to change to
> 1. crashkernel=XM,low or crashkernel=XM
> 2. crashkernel=XM,high
> 3. crashkernel=XM,high crashkernel=YM,low
>
> looks like you change your mind, now you are agreeing on
> some could low and some could be high.
>

It sounds that the "never DMA'd to memory" notion requires that we have
some low memory for the iommu, no?

Or am I misunderstanding what you are asking here?

-hpa


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