On Wed, Mar 13, 2019 at 05:09:40PM +0000, Patrick Bellasi wrote:

On 13-Mar 15:32, Peter Zijlstra wrote:

quoted

I still think that this effective thing is backwards.

With respect to the previous v6, I've now moved this concept to the
patch where we actually use it for the first time.

The "effective" values allows to efficiently enforce the most
restrictive clamp value for a task at enqueue time by:
 - not loosing track of the original request
 - don't caring about updating non runnable tasks

My point is that you already had an effective value; namely p->uclamp[],
since patch 1.

This patch then changes that into something else, instead of adding
p->uclamp_orig[], and concequently has to update all sites that
previously used p->uclamp[], which is a lot of pointless churn.