rcu: add grace-period age and more kthread state to tracing

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / rcutree.c

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index bb84deca3319bc114845cfbf88518f89bd1556d9..27b6d8de82f6ddfdfa40b56f8dab343e0eef5835 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -92,6 +92,7 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active);
  */
 static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task);
 DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
+DEFINE_PER_CPU(int, rcu_cpu_kthread_cpu);
 static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq);
 DEFINE_PER_CPU(char, rcu_cpu_has_work);
 static char rcu_kthreads_spawnable;
@@ -888,6 +889,8 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
 static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags)
        __releases(rcu_get_root(rsp)->lock)
 {
+       unsigned long gp_duration;
+
        WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
 
        /*
@@ -895,6 +898,9 @@ static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags)
         * is seen before the assignment to rsp->completed.
         */
        smp_mb(); /* See above block comment. */
+       gp_duration = jiffies - rsp->gp_start;
+       if (gp_duration > rsp->gp_max)
+               rsp->gp_max = gp_duration;
        rsp->completed = rsp->gpnum;
        rsp->signaled = RCU_GP_IDLE;
        rcu_start_gp(rsp, flags);  /* releases root node's rnp->lock. */
@@ -1583,12 +1589,15 @@ static int rcu_cpu_kthread_should_stop(int cpu)
               smp_processor_id() != cpu) {
                if (kthread_should_stop())
                        return 1;
+               per_cpu(rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
+               per_cpu(rcu_cpu_kthread_cpu, cpu) = raw_smp_processor_id();
                local_bh_enable();
                schedule_timeout_uninterruptible(1);
                if (!cpumask_equal(&current->cpus_allowed, cpumask_of(cpu)))
                        set_cpus_allowed_ptr(current, cpumask_of(cpu));
                local_bh_disable();
        }
+       per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu;
        return 0;
 }
 
@@ -1656,6 +1665,7 @@ static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu)
        if (IS_ERR(t))
                return PTR_ERR(t);
        kthread_bind(t, cpu);
+       per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu;
        WARN_ON_ONCE(per_cpu(rcu_cpu_kthread_task, cpu) != NULL);
        per_cpu(rcu_cpu_kthread_task, cpu) = t;
        wake_up_process(t);