From: Ankur Arora <ankur.a.arora@xxxxxxxxxx> Update comment in __cond_resched() clarifying how urgently needed quiescent state are provided. Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx> Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx> --- kernel/sched/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 165c90ba64ea..d328707626e3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7289,7 +7289,7 @@ int __sched __cond_resched(void) return 1; } /* - * In preemptible kernels, ->rcu_read_lock_nesting tells the tick + * In PREEMPT_RCU kernels, ->rcu_read_lock_nesting tells the tick * whether the current CPU is in an RCU read-side critical section, * so the tick can report quiescent states even for CPUs looping * in kernel context. In contrast, in non-preemptible kernels, @@ -7298,6 +7298,8 @@ int __sched __cond_resched(void) * RCU quiescent state. Therefore, the following code causes * cond_resched() to report a quiescent state, but only when RCU * is in urgent need of one. + * A third case, preemptible, but non-PREEMPT_RCU provides for + * urgently needed quiescent states via rcu_flavor_sched_clock_irq(). */ #ifndef CONFIG_PREEMPT_RCU rcu_all_qs(); -- 2.39.5 (Apple Git-154)
