From 4ea355b5368bde0574c12430df53334c4be3bdcf Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 28 Jun 2013 18:15:14 +1000 Subject: [PATCH] powerpc/perf: Don't enable if we have zero events In power_pmu_enable() we still enable the PMU even if we have zero events. This should have no effect but doesn't make much sense. Instead just return after telling the hypervisor that we are not using the PMCs. Signed-off-by: Michael Ellerman CC: [v3.10] Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/perf/core-book3s.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index 1bb26d586e3c..c91dc43e04de 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -926,6 +926,11 @@ static void power_pmu_enable(struct pmu *pmu) if (!cpuhw->disabled) goto out; + if (cpuhw->n_events == 0) { + ppc_set_pmu_inuse(0); + goto out; + } + cpuhw->disabled = 0; /* @@ -937,8 +942,6 @@ static void power_pmu_enable(struct pmu *pmu) if (!cpuhw->n_added) { mtspr(SPRN_MMCRA, cpuhw->mmcr[2] & ~MMCRA_SAMPLE_ENABLE); mtspr(SPRN_MMCR1, cpuhw->mmcr[1]); - if (cpuhw->n_events == 0) - ppc_set_pmu_inuse(0); goto out_enable; }