Re: [PATCH HACK RFC] cpu: Prevent late-arriving interrupts from disrupting offline

[Dietmar Eggemann]

On 6/8/19 6:41 PM, Paul E. McKenney wrote:
> On Tue, Jun 04, 2019 at 03:29:32PM +0200, Dietmar Eggemann wrote:
> > On 6/4/19 9:45 AM, Paul E. McKenney wrote:
> > > On Mon, Jun 03, 2019 at 03:39:18PM +0200, Dietmar Eggemann wrote:
> > > > On 6/3/19 1:44 PM, Mark Rutland wrote:
> > > > > On Mon, Jun 03, 2019 at 10:38:48AM +0200, Peter Zijlstra wrote:
> > > > > > On Sat, Jun 01, 2019 at 06:12:53PM -0700, Paul E. McKenney wrote:
> > > > > > > Scheduling-clock interrupts can arrive late in the CPU-offline process,

[...]

> > > And it looks like the reason I dropped it was that I didn't get any
> > > response from the maintainer.  I sent a message to this effect to
> > > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx and linux@xxxxxxxxxxxxxxxx on May
> > > 21, 2015.
> > >
> > > So here it is again.  ;-)
> > >
> > > I have queued this locally.  Left to myself, I add the two of you on its
> > > Cc: list and run it through my normal process.  But given the history,
> > > I would still want either an ack from the maintainer or, better, for
> > > the maintainer to take the patch.
> > >
> > > Or is there a better way for us to proceed on this?
> >
> > You could send this patch also to
> > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx and cc rmk to get his opinion
> > on the patch.
>
> OK, please let me know how the testing goes.  My thought is to send the
> patch as you suggest with your Tested-by.

Tested your patch on top of v5.2-rc4* on Arm TC2 (32bit) and CPU hotplug 
stress test. W/o your patch, the test fails within seconds since CPUs 
are not coming up again. W/ your patch, the test runs for hours just fine.

You can add my:

Tested-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>

* just for the record: one additional unrelated patch (to disable the 
NOR flash) is necessary on Arm TC2: 
https://patchwork.kernel.org/patch/10968391 .