On 29/05/18 22:52, Jeremy Linton wrote:

Hi,

On 05/29/2018 10:51 AM, Geert Uytterhoeven wrote:

quoted

Hi Will,

On Tue, May 29, 2018 at 5:08 PM, Will Deacon [off-list ref] wrote:

quoted

On Tue, May 29, 2018 at 02:18:40PM +0100, Sudeep Holla wrote:

quoted

On 29/05/18 12:56, Geert Uytterhoeven wrote:

quoted

On Tue, May 29, 2018 at 1:14 PM, Sudeep Holla
[off-list ref] wrote:

quoted

On 29/05/18 11:48, Geert Uytterhoeven wrote:

quoted

System supend still works fine on systems with big cores only:

???? R-Car H3 ES1.0 (4xCA57 (4xCA53 disabled in firmware))
???? R-Car M3-N (2xCA57)

Reverting this commit fixes the issue for me.

I can't find anything that relates to system suspend in these patches
unless they are messing with something during CPU hot plug-in back
during resume.

It's only the last patch that introduces the breakage.

As specified in the commit log, it won't change any behavior for DT
systems if it's non-NUMA or single node system. So I am still wondering
what could trigger this regression.

I wonder if we're somehow giving an uninitialised/invalid NUMA
configuration
to the scheduler, although I can't see how this would happen.

Geert -- if you enable CONFIG_DEBUG_PER_CPU_MAPS=y and apply the diff
below
do you see anything shouting in dmesg?

Thanks, but unfortunately it doesn't help.
I added some debug code to print cpumask, but so far I don't see anything
suspicious.

I suspect most of the problem is related to the node mask changing at
unexpected times (particularly cores being removed from the mask). Once
I understand that more, there may be a simpler patch.

OTOH, I've been testing with this, and with it, I can't seem to
duplicate the problem with CONFIG_NUMA disabled I found.

I am also giving it a run on my Juno(defconfig - CONFIG_NUMA) and CPU
hotplug tests are fine with this change.

-- 
Regards,
Sudeep