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

Hi, sorry for the late reply.

On Fri, Oct 29, 2021 at 4:37 PM Mel Gorman [off-list ref] 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?