diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_osnoise.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 2aa3efdca755..5e3c62a08fc0 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -1387,6 +1387,26 @@ static int run_osnoise(void) } /* + * In some cases, notably when running on a nohz_full CPU with + * a stopped tick PREEMPT_RCU has no way to account for QSs. + * This will eventually cause unwarranted noise as PREEMPT_RCU + * will force preemption as the means of ending the current + * grace period. We avoid this problem by calling + * rcu_momentary_dyntick_idle(), which performs a zero duration + * EQS allowing PREEMPT_RCU to end the current grace period. + * This call shouldn't be wrapped inside an RCU critical + * section. + * + * Note that in non PREEMPT_RCU kernels QSs are handled through + * cond_resched() + */ + if (IS_ENABLED(CONFIG_PREEMPT_RCU)) { + local_irq_disable(); + rcu_momentary_dyntick_idle(); + local_irq_enable(); + } + + /* * For the non-preemptive kernel config: let threads runs, if * they so wish. */ |