Re: [PATCH] mm/vmscan: respect cpuset policy during page demotion

Huang, Ying
2022-10-31T08:51:11Z

Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org> writes:

> On Fri 28-10-22 07:22:27, Huang, Ying wrote:
>> Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org> writes:
>>
>> > On Thu 27-10-22 17:31:35, Huang, Ying wrote:
> [...]
>> >> I think that it's possible for different processes have different
>> >> requirements.
>> >>
>> >> - Some processes don't care about where the memory is placed, prefer
>> >> local, then fall back to remote if no free space.
>> >>
>> >> - Some processes want to avoid cross-socket traffic, bind to nodes of
>> >> local socket.
>> >>
>> >> - Some processes want to avoid to use slow memory, bind to fast memory
>> >> node only.
>> >
>> > Yes, I do understand that. Do you have any specific examples in mind?
>> > [...]
>>
>> Sorry, I don't have specific examples.
>
> OK, then let's stop any complicated solution right here then. Let's
> start simple with a per-mm flag to disable demotion of an address
> space.

I'm not a big fan of per-mm flag. Because we don't have users for that
too and it needs to add ABI too.

> Should there ever be a real demand for a more fine grained solution
> let's go further but I do not think we want a half baked solution
> without real usecases.

I'm OK to ignore per-task (and missing per-process) memory policy
support for now.

Best Regards,
Huang, Ying