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authorStephane Eranian <eranian@google.com>2012-02-02 12:04:01 +0100
committerIngo Molnar <mingo@elte.hu>2012-02-03 08:24:40 +0100
commit84f2b9b2edc09595569c7397cc3c888764ffd78b (patch)
treef959f7f5746b3dc8409b2aae9584101c9b2f71a1 /arch
parent6c073a7ee250118b8be3a2379c96fd7f78382b06 (diff)
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perf: Remove deprecated WARN_ON_ONCE()
With the new throttling/unthrottling code introduced with commit: e050e3f0a71b ("perf: Fix broken interrupt rate throttling") we occasionally hit two WARN_ON_ONCE() checks in: - intel_pmu_pebs_enable() - intel_pmu_lbr_enable() - x86_pmu_start() The assertions are no longer problematic. There is a valid path where they can trigger but it is harmless. The assertion can be triggered with: $ perf record -e instructions:pp .... Leading to paths: intel_pmu_pebs_enable intel_pmu_enable_event x86_perf_event_set_period x86_pmu_start perf_adjust_freq_unthr_context perf_event_task_tick scheduler_tick And: intel_pmu_lbr_enable intel_pmu_enable_event x86_perf_event_set_period x86_pmu_start perf_adjust_freq_unthr_context. perf_event_task_tick scheduler_tick cpuc->enabled is always on because when we get to perf_adjust_freq_unthr_context() the PMU is not totally disabled. Furthermore when we need to adjust a period, we only stop the event we need to change and not the entire PMU. Thus, when we re-enable, cpuc->enabled is already set. Note that when we stop the event, both pebs and lbr are stopped if necessary (and possible). Signed-off-by: Stephane Eranian <eranian@google.com> Cc: peterz@infradead.org Link: http://lkml.kernel.org/r/20120202110401.GA30911@quad Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/perf_event.c3
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel_ds.c1
-rw-r--r--arch/x86/kernel/cpu/perf_event_intel_lbr.c2
3 files changed, 0 insertions, 6 deletions
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 5adce1040b1..2a30e5ae6ac 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -986,9 +986,6 @@ static void x86_pmu_start(struct perf_event *event, int flags)
struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);
int idx = event->hw.idx;
- if (WARN_ON_ONCE(!(event->hw.state & PERF_HES_STOPPED)))
- return;
-
if (WARN_ON_ONCE(idx == -1))
return;
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 73da6b64f5b..d6bd49faa40 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -439,7 +439,6 @@ void intel_pmu_pebs_enable(struct perf_event *event)
hwc->config &= ~ARCH_PERFMON_EVENTSEL_INT;
cpuc->pebs_enabled |= 1ULL << hwc->idx;
- WARN_ON_ONCE(cpuc->enabled);
if (x86_pmu.intel_cap.pebs_trap && event->attr.precise_ip > 1)
intel_pmu_lbr_enable(event);
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index 3fab3de3ce9..47a7e63bfe5 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -72,8 +72,6 @@ void intel_pmu_lbr_enable(struct perf_event *event)
if (!x86_pmu.lbr_nr)
return;
- WARN_ON_ONCE(cpuc->enabled);
-
/*
* Reset the LBR stack if we changed task context to
* avoid data leaks.