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

From: Dietmar Eggemann
Date: Tue Jun 11 2019 - 09:19:28 EST

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: .