rcu: Event-trace markers for computing RCU CPU utilization

[pandora-kernel.git] / kernel / rcutree.c

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 45dcc20..2a9643b 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -184,8 +184,10 @@ void rcu_bh_qs(int cpu)
  */
 void rcu_note_context_switch(int cpu)
 {
+       trace_rcu_utilization("Start context switch");
        rcu_sched_qs(cpu);
        rcu_preempt_note_context_switch(cpu);
+       trace_rcu_utilization("End context switch");
 }
 EXPORT_SYMBOL_GPL(rcu_note_context_switch);
 
@@ -1275,6 +1277,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
  */
 void rcu_check_callbacks(int cpu, int user)
 {
+       trace_rcu_utilization("Start scheduler-tick");
        if (user ||
            (idle_cpu(cpu) && rcu_scheduler_active &&
             !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
@@ -1308,6 +1311,7 @@ void rcu_check_callbacks(int cpu, int user)
        rcu_preempt_check_callbacks(cpu);
        if (rcu_pending(cpu))
                invoke_rcu_core();
+       trace_rcu_utilization("End scheduler-tick");
 }
 
 #ifdef CONFIG_SMP
@@ -1369,10 +1373,14 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
        unsigned long flags;
        struct rcu_node *rnp = rcu_get_root(rsp);
 
-       if (!rcu_gp_in_progress(rsp))
+       trace_rcu_utilization("Start fqs");
+       if (!rcu_gp_in_progress(rsp)) {
+               trace_rcu_utilization("End fqs");
                return;  /* No grace period in progress, nothing to force. */
+       }
        if (!raw_spin_trylock_irqsave(&rsp->fqslock, flags)) {
                rsp->n_force_qs_lh++; /* Inexact, can lose counts.  Tough! */
+               trace_rcu_utilization("End fqs");
                return; /* Someone else is already on the job. */
        }
        if (relaxed && ULONG_CMP_GE(rsp->jiffies_force_qs, jiffies))
@@ -1421,11 +1429,13 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
                raw_spin_unlock(&rsp->fqslock); /* irqs remain disabled */
                rsp->fqs_need_gp = 0;
                rcu_start_gp(rsp, flags); /* releases rnp->lock */
+               trace_rcu_utilization("End fqs");
                return;
        }
        raw_spin_unlock(&rnp->lock);  /* irqs remain disabled */
 unlock_fqs_ret:
        raw_spin_unlock_irqrestore(&rsp->fqslock, flags);
+       trace_rcu_utilization("End fqs");
 }
 
 #else /* #ifdef CONFIG_SMP */
@@ -1481,6 +1491,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
  */
 static void rcu_process_callbacks(struct softirq_action *unused)
 {
+       trace_rcu_utilization("Start RCU core");
        __rcu_process_callbacks(&rcu_sched_state,
                                &__get_cpu_var(rcu_sched_data));
        __rcu_process_callbacks(&rcu_bh_state, &__get_cpu_var(rcu_bh_data));
@@ -1488,6 +1499,7 @@ static void rcu_process_callbacks(struct softirq_action *unused)
 
        /* If we are last CPU on way to dyntick-idle mode, accelerate it. */
        rcu_needs_cpu_flush();
+       trace_rcu_utilization("End RCU core");
 }
 
 /*
@@ -1910,6 +1922,7 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
        struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, cpu);
        struct rcu_node *rnp = rdp->mynode;
 
+       trace_rcu_utilization("Start CPU hotplug");
        switch (action) {
        case CPU_UP_PREPARE:
        case CPU_UP_PREPARE_FROZEN:
@@ -1945,6 +1958,7 @@ static int __cpuinit rcu_cpu_notify(struct notifier_block *self,
        default:
                break;
        }
+       trace_rcu_utilization("End CPU hotplug");
        return NOTIFY_OK;
 }