perf/x86/intel/uncore: Register the PMU only if the uncore pci device exists

Current code registers PMUs for all possible uncore pci devices.
This is not good because, on some machines, one or more uncore pci
devices can be missing. The missing pci device make corresponding
PMU unusable. Register the PMU only if the uncore device exists.

Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409872109-31645-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
index 2b0fa02268b77fc19107eafbafb3e685b2f4ea71..42d00e53175dd21e46379772553af91e1393004b 100644 (file)
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
@@ -793,6 +793,7 @@ static int uncore_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id
        struct intel_uncore_box *box;
        struct intel_uncore_type *type;
        int phys_id;
+       bool first_box = false;
 
        phys_id = uncore_pcibus_to_physid[pdev->bus->number];
        if (phys_id < 0)
@@ -827,9 +828,13 @@ static int uncore_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id
        pci_set_drvdata(pdev, box);
 
        raw_spin_lock(&uncore_box_lock);
+       if (list_empty(&pmu->box_list))
+               first_box = true;
        list_add_tail(&box->list, &pmu->box_list);
        raw_spin_unlock(&uncore_box_lock);
 
+       if (first_box)
+               uncore_pmu_register(pmu);
        return 0;
 }
 
@@ -838,6 +843,7 @@ static void uncore_pci_remove(struct pci_dev *pdev)
        struct intel_uncore_box *box = pci_get_drvdata(pdev);
        struct intel_uncore_pmu *pmu;
        int i, cpu, phys_id = uncore_pcibus_to_physid[pdev->bus->number];
+       bool last_box = false;
 
        box = pci_get_drvdata(pdev);
        if (!box) {
@@ -859,6 +865,8 @@ static void uncore_pci_remove(struct pci_dev *pdev)
 
        raw_spin_lock(&uncore_box_lock);
        list_del(&box->list);
+       if (list_empty(&pmu->box_list))
+               last_box = true;
        raw_spin_unlock(&uncore_box_lock);
 
        for_each_possible_cpu(cpu) {
@@ -870,6 +878,9 @@ static void uncore_pci_remove(struct pci_dev *pdev)
 
        WARN_ON_ONCE(atomic_read(&box->refcnt) != 1);
        kfree(box);
+
+       if (last_box)
+               perf_pmu_unregister(&pmu->pmu);
 }
 
 static int __init uncore_pci_init(void)
@@ -1221,14 +1232,6 @@ static int __init uncore_pmus_register(void)
                }
        }
 
-       for (i = 0; uncore_pci_uncores[i]; i++) {
-               type = uncore_pci_uncores[i];
-               for (j = 0; j < type->num_boxes; j++) {
-                       pmu = &type->pmus[j];
-                       uncore_pmu_register(pmu);
-               }
-       }
-
        return 0;
 }