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

From: KOSAKI Motohiro
Date: Thu Jan 17 2013 - 15:20:49 EST


On 1/16/2013 8:49 PM, Tang Chen wrote:
> On 01/17/2013 06:52 AM, H. Peter Anvin wrote:
>> On 01/16/2013 01:29 PM, Andrew Morton wrote:
>>>>
>>>> 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?
>>>
>>
>> Yes,
>
> Hi HPA, Andrew,
>
> No, I don't think so. In my [PATCH v4 3/6], I checked if users specified the
> unhotpluggable memory ranges, I will remove them from movablecore_map.map[].
> So this option will not override SRAT.
>
> It works like this:
>
> hotpluggable ranges: |-----------------|
> unhotpluggable ranges: |-----| |--------|
> user specified ranges: |---| |--------------------|
> movablecore_map.map[]: |------------|
>
> Please refer to https://lkml.org/lkml/2012/12/19/53.
>
> But in this v5 patch-set, I remove all SRAT related code. So this v5 users'
> option will override SRAT.

Again, boot option is often used for workaround of firmware bugs. so, if you
make a boot option, it should be override firmware info.



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