Messages in this thread Patch in this message | | | Date | Wed, 10 Jun 2015 23:57:44 +0100 | From | Russell King - ARM Linux <> | Subject | Re: [PATCH v5] ARM: smp: Only expose /sys/.../cpuX/online if hotpluggable |
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On Tue, Jun 09, 2015 at 12:08:28PM -0700, Stephen Boyd wrote: > 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 <mark.rutland@arm.com> > >> Cc: Nicolas Pitre <nico@linaro.org> > >> Cc: Dave Martin <Dave.Martin@arm.com> > >> Acked-by: Simon Horman <horms@verge.net.au> [shmobile portion] > >> Tested-by: Simon Horman <horms@verge.net.au> > >> Cc: Magnus Damm <magnus.damm@gmail.com> > >> Cc: <linux-sh@vger.kernel.org> > >> Cc: Tyler Baker <tyler.baker@linaro.org> > >> Cc: Geert Uytterhoeven <geert@linux-m68k.org> > >> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> > > 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?
The version you've put in the patch tracker is not the version you posted. It contains this change:
diff --git a/arch/arm/mach-shmobile/common.h b/arch/arm/mach-shmobile/common.h index 476092b86c6e..f2c4bf437ea7 100644 --- a/arch/arm/mach-shmobile/common.h +++ b/arch/arm/mach-shmobile/common.h @@ -13,7 +13,8 @@ extern void shmobile_smp_boot(void); extern void shmobile_smp_sleep(void); extern void shmobile_smp_hook(unsigned int cpu, unsigned long fn, unsigned long arg); -extern int shmobile_smp_cpu_disable(unsigned int cpu); +extern bool shmobile_smp_cpu_can_disable(unsigned int cpu); +extern void shmobile_invalidate_start(void);
which your original patch did not include. The tree I'm applying to (-rc1) contains:
extern int shmobile_smp_cpu_disable(unsigned int cpu); extern void shmobile_invalidate_start(void);
there. Hence git quite rightfully declines to apply the patch. Please fix.
Thanks.
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