Re: [PATCH -V11 8/9] mm/vmscan: never demote for memcg reclaim

[Dave Hansen]

On 7/21/21 2:38 PM, Zi Yan wrote:
> On 21 Jul 2021, at 2:39, Huang Ying wrote:
>> From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
>>
>> Global reclaim aims to reduce the amount of memory used on a
>> given node or set of nodes.  Migrating pages to another node
>> serves this purpose.
>>
>> memcg reclaim is different.  Its goal is to reduce the total
>> memory consumption of the entire memcg, across all nodes.
>> Migration does not assist memcg reclaim because it just moves
>> page contents between nodes rather than actually reducing memory
>> consumption.
...
> Should this be folded into Patch 4 when can_demote() is
> introduced?

I guess it could be.  But, it's logically separate since it has its
own justification which is rather discrete.

I think it's best to keep it separate.