Re: [PATCH v3 2/2] mm: Introduce kernelcore=mirror option

[Xishi Qiu]

On 2015/12/17 10:53, Kamezawa Hiroyuki wrote:

> On 2015/12/17 11:47, Xishi Qiu wrote:
>> On 2015/12/17 9:38, Izumi, Taku wrote:
>>
>>> Dear Xishi,
>>>
>>>   Sorry for late.
>>>
>>>> -----Original Message-----
>>>> From: Xishi Qiu [mailto:qiuxishi@xxxxxxxxxx]
>>>> Sent: Friday, December 11, 2015 6:44 PM
>>>> To: Izumi, Taku/泉 拓
>>>> Cc: Luck, Tony; linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; akpm@xxxxxxxxxxxxxxxxxxxx; Kamezawa, Hiroyuki/亀澤 寛
>>>> 之; mel@xxxxxxxxx; Hansen, Dave; matt@xxxxxxxxxxxxxxxxxxx
>>>> Subject: Re: [PATCH v3 2/2] mm: Introduce kernelcore=mirror option
>>>>
>>>> On 2015/12/11 13:53, Izumi, Taku wrote:
>>>>
>>>>> Dear Xishi,
>>>>>
>>>>>> Hi Taku,
>>>>>>
>>>>>> Whether it is possible that we rewrite the fallback function in buddy system
>>>>>> when zone_movable and mirrored_kernelcore are both enabled?
>>>>>
>>>>>    What does "when zone_movable and mirrored_kernelcore are both enabled?" mean ?
>>>>>
>>>>>    My patchset just provides a new way to create ZONE_MOVABLE.
>>>>>
>>>>
>>>> Hi Taku,
>>>>
>>
>> Hi Taku,
>>
>> We can NOT specify kernelcore= "nn[KMG]" and "mirror" at the same time.
>> So when we use "mirror", in fact, the movable zone is a new zone. I think it is
>> more appropriate with this name "mirrored zone", and also we can rewrite the
>> fallback function in buddy system in this case.
> 
> kernelcore ="mirrored zone" ?

No, it's zone_names[MAX_NR_ZONES]
How about "Movable", -> "Non-mirrored"?

> 
> BTW, let me confirm.
> 
>   ZONE_NORMAL = mirrored
>   ZONE_MOVABLE = not mirrored.
> 

Yes, 

> so, the new zone is "not-mirrored" zone.
> 
> Now, fallback function is
> 
>    movable -> normal -> DMA.
> 
> As Tony requested, we may need a knob to stop a fallback in "movable->normal", later.
> 

If the mirrored memory is small and the other is large,
I think we can both enable "non-mirrored -> normal" and "normal -> non-mirrored".

Thanks,
Xishi Qiu

> Thanks,
> -Kame
> 
> 
> 
> 
> 
> 
> 
> .
> 



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