Re: [PATCH v8 2/6] rcu/segcblist: Add counters to segcblist datastructure

[Frederic Weisbecker]

On Mon, Oct 26, 2020 at 01:45:57AM -0400, Joel Fernandes wrote:
> On Mon, Oct 26, 2020 at 01:50:58AM +0100, Frederic Weisbecker wrote:
> > On Wed, Oct 21, 2020 at 03:08:09PM -0400, Joel Fernandes (Google) wrote:
> > >  bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq)
> > >  {
> > > -	int i;
> > > +	int i, j;
> > >  
> > >  	WARN_ON_ONCE(!rcu_segcblist_is_enabled(rsclp));
> > >  	if (rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL))
> > > @@ -487,6 +508,10 @@ bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq)
> > >  	if (rcu_segcblist_restempty(rsclp, i) || ++i >= RCU_NEXT_TAIL)
> > >  		return false;
> > >  
> > > +	/* Accounting: everything below i is about to get merged into i. */
> > > +	for (j = i + 1; j <= RCU_NEXT_TAIL; j++)
> > > +		rcu_segcblist_move_seglen(rsclp, j, i);
> > > +
> > 
> > Can you perhaps reuse the below loop to move the seglen?
> 
> Not easily, because we will need to store 'i' into another variable then, which
> does not change.
> 
> Besides IMHO, the code is more readable with the loops separated.

Works for me.

Thanks!