Re: [RFC PATCH] sched/numa: fix bug in update_task_scan_period

From: Mel Gorman
Date: Fri Aug 14 2020 - 09:16:02 EST

On Wed, Aug 12, 2020 at 11:51:54AM +0800, ????????? wrote:
> OK. Thanks for your advice and I'll use label instead.
> In the case of migration failures, if there are still new failures after
> clearing (meaning the node is still overloaded), the scanning period would
> be doubled, just like not using this patch. However, if the failures do not
> increase again, then the scanning period should be adjusted according to the
> following rules (i.e., ps and lr ratio). I believe this is the original
> design idea, right?

The original idea was to simply throttle scanning if the faults were
useless. Your patch is probably correct but I would still like to see
some evidence of the user-visible impact. What tests have you conducted
to make sure it behaves better (or is at least neutral in most cases)?

Mel Gorman