Re: [RFC][PATCH v2 08/11] context_tracking,rcu: Replace RCU dynticks counter with context_tracking

From: Paul E. McKenney
Date: Wed Sep 29 2021 - 15:45:42 EST


On Wed, Sep 29, 2021 at 09:24:31PM +0200, Peter Zijlstra wrote:
> On Wed, Sep 29, 2021 at 09:13:26PM +0200, Peter Zijlstra wrote:
> > On Wed, Sep 29, 2021 at 11:37:01AM -0700, Paul E. McKenney wrote:
> >
> > > And what happens to all of this in !CONFIG_CONTEXT_TRACKING kernels?
> > > Of course, RCU needs it unconditionally. (There appear to be at least
> > > parts of it that are unconditionally available, but I figured that I
> > > should ask. Especially given the !CONFIG_CONTEXT_TRACKING definition
> > > of the __context_tracking_cpu_seq() function.)
> >
> > For !CONFIG_CONTEXT_TRACKING it goes *poof*.
> >
> > Since the thing was called dynticks, I presumed it was actually dynticks
> > only, silly me (also, I didn't see any obvious !context_tracking usage
> > of it, i'll go audit it more carefully.
>
> Oh argh, it does idle too... damn. And I don't suppose having 2 counters
> is going to be nice :/
>
> I'll go back to thinking about this.

Glad I could help? For some definition of "help"? ;-)

Thanx, Paul