Re: [PATCH v5 6/9] mm/demotion: Add support for removing node from demotion memory tiers

Aneesh Kumar K V
2022-06-08T09:04:08Z

On 6/8/22 12:29 PM, Ying Huang wrote:
> On Fri, 2022-06-03 at 19:12 +0530, Aneesh Kumar K.V wrote:
>> This patch adds the special string "none" as a supported memtier value
>> that we can use to remove a specific node from being using as demotion target.
>>
>> For ex:
>> :/sys/devices/system/node/node1# cat memtier
>> 1
>> :/sys/devices/system/node/node1# cat ../../memtier/memtier1/nodelist
>> 1-3
>> :/sys/devices/system/node/node1# echo none > memtier
>> :/sys/devices/system/node/node1#
>> :/sys/devices/system/node/node1# cat memtier
>> :/sys/devices/system/node/node1# cat ../../memtier/memtier1/nodelist
>> 2-3
>> :/sys/devices/system/node/node1#
>
> Do you have a practical use case for this? What kind of memory node
> needs to be removed from memory tiers demotion/promotion?
>

This came up in our internal discussion. It was mentioned that there is
a need to skip some slow memory nodes from participating in demotion.

-aneesh