Re: Re: Re: [PATCH v1] sched/numa: add per-process numa_balancing

[李港]

Hi, sorry for the late reply.

On Fri, Oct 29, 2021 at 4:37 PM Mel Gorman <mgorman@xxxxxxx> wrote:
>
> My point is that as it stands,
> prctl(PR_NUMA_BALANCING,PR_SET_NUMA_BALANCING,1) either does nothing or
> fails. If per-process numa balancing is to be introduced, it should have
> meaning with the global tuning affecting default behaviour and the prctl
> affecting specific behaviour.
>

If the global tuning affects default behaviour and the prctl
affects specific behaviour.  Then when prctl specifies
numa_balancing for a process, there is no way for the
global tuning to affect that process. In other words, global tuning
become a default value, not a switch for global numa_balancing.

My idea is that the global numa_balancning still has absolute control, and prctl
can only optionally turn off numa_balancing for process when the global is on.
After all, It is more common to enable global numa_balancing and disable it in
several processes than to disable global numa_balancing and enable it in
several processes.

This is my personal opinion, what do you think.
:-)

Do we need the global to be a switch, or a default value?