From: Zhou Chengming Date: Mon, 16 Jan 2017 03:21:11 +0000 (+0800) Subject: perf/x86/intel: Handle exclusive threadid correctly on CPU hotplug X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=4e71de7986386d5fd3765458f27d612931f27f5e;p=linux-beck.git perf/x86/intel: Handle exclusive threadid correctly on CPU hotplug The CPU hotplug function intel_pmu_cpu_starting() sets cpu_hw_events.excl_thread_id unconditionally to 1 when the shared exclusive counters data structure is already availabe for the sibling thread. This works during the boot process because the first sibling gets threadid 0 assigned and the second sibling which shares the data structure gets 1. But when the first thread of the core is offlined and onlined again it shares the data structure with the second thread and gets exclusive thread id 1 assigned as well. Prevent this by checking the threadid of the already online thread. [ tglx: Rewrote changelog ] Signed-off-by: Zhou Chengming Cc: NuoHan Qiao Cc: ak@linux.intel.com Cc: peterz@infradead.org Cc: kan.liang@intel.com Cc: dave.hansen@linux.intel.com Cc: eranian@google.com Cc: qiaonuohan@huawei.com Cc: davidcc@google.com Cc: guohanjun@huawei.com Link: http://lkml.kernel.org/r/1484536871-3131-1-git-send-email-zhouchengming1@huawei.com Signed-off-by: Thomas Gleixner --- --- arch/x86/events/intel/core.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index d611cab214a6..eb1484c86bb4 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -3176,13 +3176,16 @@ static void intel_pmu_cpu_starting(int cpu) if (x86_pmu.flags & PMU_FL_EXCL_CNTRS) { for_each_cpu(i, topology_sibling_cpumask(cpu)) { + struct cpu_hw_events *sibling; struct intel_excl_cntrs *c; - c = per_cpu(cpu_hw_events, i).excl_cntrs; + sibling = &per_cpu(cpu_hw_events, i); + c = sibling->excl_cntrs; if (c && c->core_id == core_id) { cpuc->kfree_on_online[1] = cpuc->excl_cntrs; cpuc->excl_cntrs = c; - cpuc->excl_thread_id = 1; + if (!sibling->excl_thread_id) + cpuc->excl_thread_id = 1; break; } }