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

[Tang Chen <tangchen@cn.fujitsu.com>]

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.


Thanks. :)

>but we still need a higher-level user interface which specifies
> which nodes, not which memory ranges, should be movable.  That is the
> policy granularity that is actually appropriate for the administrator
> (trading off performance vs reliability.)
>
> 	-hpa
>
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