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Diffstat (limited to 'arch/x86/kernel/cpu/perf_event_intel_cqm.c')
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel_cqm.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_intel_cqm.c b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
index 188076161c1b..377e8f8ed391 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_cqm.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_cqm.c
@@ -952,6 +952,14 @@ static u64 intel_cqm_event_count(struct perf_event *event)
return 0;
/*
+ * Getting up-to-date values requires an SMP IPI which is not
+ * possible if we're being called in interrupt context. Return
+ * the cached values instead.
+ */
+ if (unlikely(in_interrupt()))
+ goto out;
+
+ /*
* Notice that we don't perform the reading of an RMID
* atomically, because we can't hold a spin lock across the
* IPIs.
@@ -1247,7 +1255,7 @@ static inline void cqm_pick_event_reader(int cpu)
cpumask_set_cpu(cpu, &cqm_cpumask);
}
-static void intel_cqm_cpu_prepare(unsigned int cpu)
+static void intel_cqm_cpu_starting(unsigned int cpu)
{
struct intel_pqr_state *state = &per_cpu(pqr_state, cpu);
struct cpuinfo_x86 *c = &cpu_data(cpu);
@@ -1288,13 +1296,11 @@ static int intel_cqm_cpu_notifier(struct notifier_block *nb,
unsigned int cpu = (unsigned long)hcpu;
switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_UP_PREPARE:
- intel_cqm_cpu_prepare(cpu);
- break;
case CPU_DOWN_PREPARE:
intel_cqm_cpu_exit(cpu);
break;
case CPU_STARTING:
+ intel_cqm_cpu_starting(cpu);
cqm_pick_event_reader(cpu);
break;
}
@@ -1365,7 +1371,7 @@ static int __init intel_cqm_init(void)
goto out;
for_each_online_cpu(i) {
- intel_cqm_cpu_prepare(i);
+ intel_cqm_cpu_starting(i);
cqm_pick_event_reader(i);
}