Hi Robin, On Tue, May 29, 2018 at 7:08 PM, Robin Murphy <robin.murphy@xxxxxxx> wrote: > On 29/05/18 16:51, Geert Uytterhoeven wrote: >> On Tue, May 29, 2018 at 5:08 PM, Will Deacon <will.deacon@xxxxxxx> wrote: >>> On Tue, May 29, 2018 at 02:18:40PM +0100, Sudeep Holla wrote: >>>> On 29/05/18 12:56, Geert Uytterhoeven wrote: >>>>> On Tue, May 29, 2018 at 1:14 PM, Sudeep Holla <sudeep.holla@xxxxxxx> >>>>> wrote: >>>>>> On 29/05/18 11:48, Geert Uytterhoeven wrote: >>>>>>> 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. > > Do you have CONFIG_NUMA enabled? On a hunch I've managed to reproduce what > looks like the same thing on a Juno board with NUMA=n; going in with > external debug it seems to be stuck in the loop in > init_sched_groups_capacity(), with an approximate stack trace of: CONFIG_NUMA is not set. I'm basically using renesas_defconfig from https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas.git/log/?h=topic/renesas-defconfig Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
