On Tue, Nov 05, 2013 at 06:01:25PM +0100, Stephane Eranian wrote:
> +static int rapl_cpu_dying(int cpu)
> +{
> + struct rapl_pmu *pmu = per_cpu(rapl_pmu, cpu);
> + struct perf_event *event, *tmp;
> +
> + if (!pmu)
> + return 0;
> +
> + spin_lock(&rapl_hotplug_lock);
> +
> + /*
> + * stop all syswide RAPL events on that CPU
> + * as a consequence also stops the hrtimer
> + */
> + list_for_each_entry_safe(event, tmp, &pmu->active_list, active_entry) {
> + rapl_pmu_event_stop(event, PERF_EF_UPDATE);
> + }
> +
> + per_cpu(rapl_pmu, cpu) = NULL;
> +
> + if (atomic_dec_and_test(&pmu->refcnt))
> + kfree(pmu);
> +
> + spin_unlock(&rapl_hotplug_lock);
> + return 0;
> +}
Could you do an add-on patch similar to the below -- no need to respin
the entire series once again for this.
---
commit 22cc4ccf63e10e361531bf61e6e6c96c53a2f665
Author: Yan, Zheng <[email protected]>
Date: Tue Apr 16 19:51:05 2013 +0800
perf/x86: Avoid kfree() in CPU_{STARTING,DYING}
On -rt kfree() can schedule, but CPU_{STARTING,DYING} should be
atomic. So use a list to defer kfree until CPU_{ONLINE,DEAD}.
Signed-off-by: Yan, Zheng <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link:
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
index 75da9e18b128..50d4a1c58106 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
@@ -2622,6 +2622,21 @@ static void __init uncore_pci_exit(void)
}
}
+/* CPU hot plug/unplug are serialized by cpu_add_remove_lock mutex */
+static LIST_HEAD(boxes_to_free);
+
+static void __cpuinit uncore_kfree_boxes(void)
+{
+ struct intel_uncore_box *box;
+
+ while (!list_empty(&boxes_to_free)) {
+ box = list_entry(boxes_to_free.next,
+ struct intel_uncore_box, list);
+ list_del(&box->list);
+ kfree(box);
+ }
+}
+
static void __cpuinit uncore_cpu_dying(int cpu)
{
struct intel_uncore_type *type;
@@ -2636,7 +2651,7 @@ static void __cpuinit uncore_cpu_dying(int cpu)
box = *per_cpu_ptr(pmu->box, cpu);
*per_cpu_ptr(pmu->box, cpu) = NULL;
if (box && atomic_dec_and_test(&box->refcnt))
- kfree(box);
+ list_add(&box->list, &boxes_to_free);
}
}
}
@@ -2666,8 +2681,11 @@ static int __cpuinit uncore_cpu_starting(int cpu)
if (exist && exist->phys_id == phys_id) {
atomic_inc(&exist->refcnt);
*per_cpu_ptr(pmu->box, cpu) = exist;
- kfree(box);
- box = NULL;
+ if (box) {
+ list_add(&box->list,
+ &boxes_to_free);
+ box = NULL;
+ }
break;
}
}
@@ -2806,6 +2824,10 @@ static int
case CPU_DYING:
uncore_cpu_dying(cpu);
break;
+ case CPU_ONLINE:
+ case CPU_DEAD:
+ uncore_kfree_boxes();
+ break;
default:
break;
}
--
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/
