perf: Default PMU ops

[firefly-linux-kernel-4.4.55.git] / kernel / perf_event.c

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 5ed0c06765bbef8d271bbafd44d6ae1b082b97c8..8ef4ba3bcb1f617966f8f050bb72cff597ac4098 100644 (file)
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -674,21 +674,14 @@ group_sched_in(struct perf_event *group_event,
 {
        struct perf_event *event, *partial_group = NULL;
        struct pmu *pmu = group_event->pmu;
-       bool txn = false;
 
        if (group_event->state == PERF_EVENT_STATE_OFF)
                return 0;
 
-       /* Check if group transaction availabe */
-       if (pmu->start_txn)
-               txn = true;
-
-       if (txn)
-               pmu->start_txn(pmu);
+       pmu->start_txn(pmu);
 
        if (event_sched_in(group_event, cpuctx, ctx)) {
-               if (txn)
-                       pmu->cancel_txn(pmu);
+               pmu->cancel_txn(pmu);
                return -EAGAIN;
        }
 
@@ -702,7 +695,7 @@ group_sched_in(struct perf_event *group_event,
                }
        }
 
-       if (!txn || !pmu->commit_txn(pmu))
+       if (!pmu->commit_txn(pmu))
                return 0;
 
 group_error:
@@ -717,8 +710,7 @@ group_error:
        }
        event_sched_out(group_event, cpuctx, ctx);
 
-       if (txn)
-               pmu->cancel_txn(pmu);
+       pmu->cancel_txn(pmu);
 
        return -EAGAIN;
 }
@@ -4965,6 +4957,31 @@ static LIST_HEAD(pmus);
 static DEFINE_MUTEX(pmus_lock);
 static struct srcu_struct pmus_srcu;
 
+static void perf_pmu_nop_void(struct pmu *pmu)
+{
+}
+
+static int perf_pmu_nop_int(struct pmu *pmu)
+{
+       return 0;
+}
+
+static void perf_pmu_start_txn(struct pmu *pmu)
+{
+       perf_pmu_disable(pmu);
+}
+
+static int perf_pmu_commit_txn(struct pmu *pmu)
+{
+       perf_pmu_enable(pmu);
+       return 0;
+}
+
+static void perf_pmu_cancel_txn(struct pmu *pmu)
+{
+       perf_pmu_enable(pmu);
+}
+
 int perf_pmu_register(struct pmu *pmu)
 {
        int ret;
@@ -4974,6 +4991,29 @@ int perf_pmu_register(struct pmu *pmu)
        pmu->pmu_disable_count = alloc_percpu(int);
        if (!pmu->pmu_disable_count)
                goto unlock;
+
+       if (!pmu->start_txn) {
+               if (pmu->pmu_enable) {
+                       /*
+                        * If we have pmu_enable/pmu_disable calls, install
+                        * transaction stubs that use that to try and batch
+                        * hardware accesses.
+                        */
+                       pmu->start_txn  = perf_pmu_start_txn;
+                       pmu->commit_txn = perf_pmu_commit_txn;
+                       pmu->cancel_txn = perf_pmu_cancel_txn;
+               } else {
+                       pmu->start_txn  = perf_pmu_nop_void;
+                       pmu->commit_txn = perf_pmu_nop_int;
+                       pmu->cancel_txn = perf_pmu_nop_void;
+               }
+       }
+
+       if (!pmu->pmu_enable) {
+               pmu->pmu_enable  = perf_pmu_nop_void;
+               pmu->pmu_disable = perf_pmu_nop_void;
+       }
+
        list_add_rcu(&pmu->entry, &pmus);
        ret = 0;
 unlock: