Re: [PATCH 2/3] softirq: avoid spurious stalls due to need_resched()

From: Paul E. McKenney
Date: Fri Mar 03 2023 - 22:11:18 EST


On Fri, Mar 03, 2023 at 05:39:21PM -0800, Jakub Kicinski wrote:
> On Fri, 3 Mar 2023 17:25:35 -0800 Paul E. McKenney wrote:
> > > Just to be sure - have you seen Peter's patches?
> > >
> > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git core/softirq
> > >
> > > I think it feeds the time limit to the callback from softirq,
> > > so the local 3ms is no more?
> >
> > I might or might not have back in September of 2020. ;-)
> >
> > But either way, the question remains: Should RCU_SOFTIRQ do time checking
> > in ksoftirqd context? Seems like the answer should be "yes", independently
> > of Peter's patches.
>
> :-o I didn't notice, I thought that's from Dec 22, LWN was writing
> about Peter's rework at that point. I'm not sure what the story is :(
> And when / if any of these changes are coming downstream.

Not a problem either way, as the compiler would complain bitterly about
the resulting merge conflict and it is easy to fix. ;-)

Thanx, Paul