Re: [PATCH 0/6] sched/numa: Complete scanning of partial and inactive VMAs

Ingo Molnar
2023-10-10T21:45:08Z

* Raghavendra K T <raghavendra.kt@amd.com> wrote:

> On 10/10/2023 2:01 PM, Mel Gorman wrote:
> > NUMA Balancing currently uses PID fault activity within a VMA to
> > determine if it is worth updating PTEs to trap NUMA hinting faults.
> > While this is reduces overhead, it misses two important corner case.
> > The first is that if Task A partially scans a VMA that is active and
> > Task B resumes the scan but is inactive, then the remainder of the VMA
> > may be missed. Similarly, if a VMA is inactive for a period of time then
> > it may never be scanned again.
> >
> > Patches 1-3 improve the documentation of the current per-VMA tracking
> > and adds a trace point for scan activity. Patch 4 addresses a corner
> > case where the PID activity information may not be reset after the
> > expected timeout. Patches 5-6 complete the scanning of partial and
> > inactive VMAs within the scan sequence.
> >
> > This could be improved further but it would deserve a separate series on
> > top with supporting data justifying the change. Otherwise and gain/loss
> > due to the additional changes could be masked by this series on its own.
> >
>
> Thank you Mel for the patches. I see Ingo already took to sched/core.
> Here is my testing detail FWIW.

Thank you for testing the series, I've added your Tested-by to the final
two patches that change behavior materially:

Tested-by: Raghavendra K T <raghavendra.kt@amd.com>

Thanks,

Ingo