Commit-ID: 22cc4ccf63e10e361531bf61e6e6c96c53a2f665
Gitweb: http://git.kernel.org/tip/22cc4ccf63e10e361531bf61e6e6c96c53a2f665
Author: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
AuthorDate: Tue, 16 Apr 2013 19:51:05 +0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 21 Apr 2013 10:59:01 +0200
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 <zheng.z.yan@xxxxxxxxx>
Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: peterz@xxxxxxxxxxxxx
Cc: eranian@xxxxxxxxxx
Cc: ak@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1366113067-3262-2-git-send-email-zheng.z.yan@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event_intel_uncore.c | 28 ++++++++++++++++++++++++---
1 file changed, 25 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
index 75da9e1..50d4a1c 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;
}
--
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