diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index 59d40c454aa0..4674b21247f7 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -421,16 +421,18 @@ TRACE_EVENT(rcu_fqs, /* * Tracepoint for dyntick-idle entry/exit events. These take a string - * as argument: "Start" for entering dyntick-idle mode, "End" for - * leaving it, "--=" for events moving towards idle, and "++=" for events - * moving away from idle. "Error on entry: not idle task" and "Error on - * exit: not idle task" indicate that a non-idle task is erroneously + * as argument: "Start" for entering dyntick-idle mode, "Startirq" for + * entering it from irq/NMI, "End" for leaving it, "Endirq" for leaving it + * to irq/NMI, "--=" for events moving towards idle, and "++=" for events + * moving away from idle. "Error on entry: not idle task" and "Error + * on exit: not idle task" indicate that a non-idle task is erroneously * toying with the idle loop. * * These events also take a pair of numbers, which indicate the nesting * depth before and after the event of interest. Note that task-related - * events use the upper bits of each number, while interrupt-related - * events use the lower bits. + * and interrupt-related events use two separate counters, and that the + * "++=" and "--=" events for irq/NMI will change the counter by two, + * otherwise by one. */ TRACE_EVENT(rcu_dyntick, diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 444aa2b3f24d..d069ba2d8412 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -880,12 +880,15 @@ void rcu_nmi_exit(void) * leave it in non-RCU-idle state. */ if (rdtp->dynticks_nmi_nesting != 1) { + trace_rcu_dyntick(TPS("--="), rdtp->dynticks_nmi_nesting, + rdtp->dynticks_nmi_nesting - 2); WRITE_ONCE(rdtp->dynticks_nmi_nesting, /* No store tearing. */ rdtp->dynticks_nmi_nesting - 2); return; } /* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */ + trace_rcu_dyntick(TPS("Startirq"), rdtp->dynticks_nmi_nesting, 0); WRITE_ONCE(rdtp->dynticks_nmi_nesting, 0); /* Avoid store tearing. */ rcu_dynticks_eqs_enter(); } @@ -1057,6 +1060,9 @@ void rcu_nmi_enter(void) rcu_dynticks_eqs_exit(); incby = 1; } + trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="), + rdtp->dynticks_nmi_nesting, + rdtp->dynticks_nmi_nesting + incby); WRITE_ONCE(rdtp->dynticks_nmi_nesting, /* Prevent store tearing. */ rdtp->dynticks_nmi_nesting + incby); barrier();