On Mon, Apr 06, 2015 at 01:24:13PM -0700, Stephen Boyd wrote: > Writes to /sys/.../cpuX/online fail if we determine the platform > doesn't support hotplug for that CPU. Furthermore, if the cpu_die > op isn't specified the system hangs when we try to offline a CPU > and it comes right back online unexpectedly. Let's figure this > stuff out before we make the sysfs nodes so that the online file > doesn't even exist if it isn't (at least sometimes) possible to > hotplug the CPU. > > Add a new 'cpu_can_disable' op and repoint all 'cpu_disable' > implementations at it because all implementers use the op to > indicate if a CPU can be hotplugged or not in a static fashion. > With PSCI we may need to add a 'cpu_disable' op so that the > secure OS can be migrated off the CPU we're trying to hotplug. > In this case, the 'cpu_can_disable' op will indicate that all > CPUs are hotpluggable by returning true, but the 'cpu_disable' op > will make a PSCI migration call and occasionally fail, denying > the hotplug of a CPU. This shouldn't be any worse than x86 where > we may indicate that all CPUs are hotpluggable but occasionally > we can't offline a CPU due to check_irq_vectors_for_cpu_disable() > failing to find a CPU to move vectors to. > > Cc: Mark Rutland <[email protected]> > Cc: Nicolas Pitre <[email protected]> > Cc: Dave Martin <[email protected]> > Cc: Simon Horman <[email protected]> > Cc: Magnus Damm <[email protected]> > Cc: <[email protected]> > Cc: Tyler Baker <[email protected]> > Cc: Geert Uytterhoeven <[email protected]> > Signed-off-by: Stephen Boyd <[email protected]>
I think this is fine, but I'd like to see some acks for it. As it's mostly core ARM stuff, it should be merged through my tree unless there is a known conflict with arm-soc. Thanks. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
