If the usage counter is non-zero there is no point to update the rmid in the PQR MSR. Signed-off-by: Thomas Gleixner --- arch/x86/kernel/cpu/perf_event_intel_cqm.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) Index: linux/arch/x86/kernel/cpu/perf_event_intel_cqm.c =================================================================== --- linux.orig/arch/x86/kernel/cpu/perf_event_intel_cqm.c +++ linux/arch/x86/kernel/cpu/perf_event_intel_cqm.c @@ -974,10 +974,12 @@ static void intel_cqm_event_start(struct event->hw.cqm_state &= ~PERF_HES_STOPPED; - if (state->cnt++) - WARN_ON_ONCE(state->rmid != rmid); - else + if (state->cnt++) { + if (!WARN_ON_ONCE(state->rmid != rmid)) + return; + } else { WARN_ON_ONCE(state->rmid); + } state->rmid = rmid; /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/