Re: [PATCH v5 0/5] Add movablecore_map boot option

From: KOSAKI Motohiro
Date: Wed Jan 16 2013 - 17:01:11 EST


On 1/16/2013 4:29 PM, Andrew Morton wrote:
> On Wed, 16 Jan 2013 15:25:44 +0900
> Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> wrote:
>
>>>
>>> Things I'm wondering:
>>>
>>> - is there *really* a case for retaining the boot option if/when
>>> SRAT support is available?
>>
>> Yes. If SRAT support is available, all memory which enabled hotpluggable
>> bit are managed by ZONEMOVABLE. But performance degradation may
>> occur by NUMA because we can only allocate anonymous page and page-cache
>> from these memory.
>>
>> In this case, if user cannot change SRAT information, user needs a way to
>> select/set removable memory manually.
>
> If I understand this correctly you mean that once SRAT parsing is
> implemented, the user can use movablecore_map to override that SRAT
> parsing, yes? That movablecore_map will take precedence over SRAT?

I think movablecore_map (I prefer movablemem than it, btw) should behave so.
because of, for past three years, almost all memory hotplug bug was handled
only I and kamezawa-san and, afaik, both don't have hotremove aware specific
hardware.

So, if the new feature require specific hardware, we can't maintain this area
any more.


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