On 04/13/2015 06:42 AM, Russell King - ARM Linux wrote: > On Fri, Apr 10, 2015 at 03:33:11PM -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]> >> Acked-by: Simon Horman <[email protected]> [shmobile portion] >> Tested-by: 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]> > Let's see some more acks for this... >
Nobody else has acked this so far. Shall I put it in the patch tracker now? Or is there someone more specific we need an ack from? -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- 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/
