On Fri, Jul 23, 2021 at 05:21:37PM +0100, Mel Gorman wrote: > I'm still not a fan because vruntime gets distorted. From the docs > > Small detail: on "ideal" hardware, at any time all tasks would have the same > p->se.vruntime value --- i.e., tasks would execute simultaneously and no task > would ever get "out of balance" from the "ideal" share of CPU time > > If yield_to impacts this "ideal share" then it could have other > consequences. Note that we already violate this ideal both subtly and explicitly. For an example of the latter consider pretty much the entirety of place_entity() with GENTLE_FAIR_SLEEPERS being the most egregious example. That said; adding to vruntime will only penalize the task itself, while subtracting from vruntime will penalize everyone else. And in that sense addition to vruntime is a safe option. I've not fully considered the case at hand; just wanted to give some context.
