powerpc/pseries/cpuidle: Replace pseries_notify_cpuidle_add call with notifier
The following patch is to remove the pseries_notify_add_cpu() call
and replace it by a hot plug notifier.
This would prevent cpuidle resources being released and allocated each
time cpu comes online on pseries.
The earlier design was causing a lockdep problem
in start_secondary as reported on this thread
-https://lkml.org/lkml/2012/5/17/2
This applies on 3.4-rc7
Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c
index e61483e..a97ef66 100644
--- a/arch/powerpc/platforms/pseries/processor_idle.c
+++ b/arch/powerpc/platforms/pseries/processor_idle.c
@@ -11,6 +11,7 @@
#include <linux/moduleparam.h>
#include <linux/cpuidle.h>
#include <linux/cpu.h>
+#include <linux/notifier.h>
#include <asm/paca.h>
#include <asm/reg.h>
@@ -186,17 +187,28 @@
.enter = &shared_cede_loop },
};
-int pseries_notify_cpuidle_add_cpu(int cpu)
+static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
+ unsigned long action, void *hcpu)
{
+ int hotcpu = (unsigned long)hcpu;
struct cpuidle_device *dev =
- per_cpu_ptr(pseries_cpuidle_devices, cpu);
- if (dev && cpuidle_get_driver()) {
- cpuidle_disable_device(dev);
- cpuidle_enable_device(dev);
+ per_cpu_ptr(pseries_cpuidle_devices, hotcpu);
+
+ switch (action & 0xf) {
+ case CPU_ONLINE:
+ if (dev && cpuidle_get_driver()) {
+ cpuidle_disable_device(dev);
+ cpuidle_enable_device(dev);
+ }
+ break;
}
- return 0;
+ return NOTIFY_OK;
}
+static struct notifier_block setup_hotplug_notifier = {
+ .notifier_call = pseries_cpuidle_add_cpu_notifier,
+};
+
/*
* pseries_cpuidle_driver_init()
*/
@@ -321,6 +333,7 @@
return retval;
}
+ register_cpu_notifier(&setup_hotplug_notifier);
printk(KERN_DEBUG "pseries_idle_driver registered\n");
return 0;
