Re: [PATCH v3] srcu: Reduce blocking agressiveness of expedited grace periods further

Paul E. McKenney
2022-07-20T18:13:21Z

On Wed, Jul 20, 2022 at 08:19:11AM +0100, Marc Zyngier wrote:
> Hi Paul,
>
> On Tue, 19 Jul 2022 18:15:47 +0100,
> "Paul E. McKenney" <paulmck@kernel.org> wrote:
> >
> > On Tue, Jul 19, 2022 at 09:25:56AM +0100, Marc Zyngier wrote:
> > >
> > > Is there any chance for this fix to make it into 5.19? The regression
> > > is significant enough on low-end systems, and I'd rather see it
> > > addressed.
> >
> > I wasn't planning on it, based on my (possibly quite flawed) assumption
> > that it affected only embedded systems running in a virtual environment.
>
> Not quite. This affects any system running virtual machines based on
> KVM and using QEMU as the VMM (the machines I run this on don't quite
> qualify as "embedded").
>
> > My plan was to send it in my pull request for the next merge window
> > next week. My pull request is next week, yes, the merge window opens
> > the following Sunday. ;-)
> >
> > It has a Fixes tag, so it will be backported.
> >
> > But if it is important to get it into v5.19 rather than v5.19.x for small
> > "x", please let me know and I will see what Linus does with the resulting
> > v5.19-rc7 pull request.
>
> I think that the sooner we address this in an upstream kernel, the
> better, and I'd definitely support you sending this to Linus for -rc7!

Given your and Zhangfei's Tested-by, if testing continues to go well,
I will send a pull request to Linus before the end of this week.

Thanx, Paul

> Thanks,
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.