Re: [PATCH v4 -rcu 3/4] rcu/segcblist: Add counters to segcblist datastructure

From: Paul E. McKenney
Date: Wed Aug 26 2020 - 10:25:07 EST


On Tue, Aug 25, 2020 at 06:51:03PM -0400, Joel Fernandes wrote:
> On Tue, Aug 25, 2020 at 02:53:38PM -0700, Paul E. McKenney wrote:
> > On Mon, Aug 24, 2020 at 10:48:41PM -0400, Joel Fernandes (Google) wrote:
> > > Add counting of segment lengths of segmented callback list.
> > >
> > > This will be useful for a number of things such as knowing how big the
> > > ready-to-execute segment have gotten. The immediate benefit is ability
> > > to trace how the callbacks in the segmented callback list change.
> > >
> > > Tested by profusely reading traces when segcblist counts updated.
> >
> > Might I recommend a more repeatable and sustainable test methodology?
> > (Sorry, couldn't resist, given that you left yourself wide open for
> > that one...)
>
> Ah, this message was from an older series :-(. I did test it with rcutorture
> for many hours. But I forgot to update this commit message. :-(

That is better. Let me see if I can find a more targeted test from the
old days...

> I will respond to other comments soon, I am still stuck on the comment about
> rcl.len and rcu_barrier interaction that you brought up in 1/4 and 2/4.

Hoping my more recent replies help. If not, you know where to find me.

Thanx, Paul