From 0cabb47af3cfaeb6007ba3868379bbd4daee64cc Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 10 Dec 2021 16:25:20 -0800 Subject: rcu: Refactor rcu_barrier() empty-list handling This commit saves a few lines by checking first for an empty callback list. If the callback list is empty, then that CPU is taken care of, regardless of its online or nocb state. Also simplify tracing accordingly and fold a few lines together. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 25 ++++++++----------------- 1 file changed, 8 insertions(+), 17 deletions(-) (limited to 'kernel/rcu') diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 73a4c9d07b86..57a7a0065750 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4030,8 +4030,7 @@ void rcu_barrier(void) /* Did someone else do our work for us? */ if (rcu_seq_done(&rcu_state.barrier_sequence, s)) { - rcu_barrier_trace(TPS("EarlyExit"), -1, - rcu_state.barrier_sequence); + rcu_barrier_trace(TPS("EarlyExit"), -1, rcu_state.barrier_sequence); smp_mb(); /* caller's subsequent code after above check. */ mutex_unlock(&rcu_state.barrier_mutex); return; @@ -4059,26 +4058,18 @@ void rcu_barrier(void) */ for_each_possible_cpu(cpu) { rdp = per_cpu_ptr(&rcu_data, cpu); - if (cpu_is_offline(cpu) && - !rcu_rdp_is_offloaded(rdp)) + if (!rcu_segcblist_n_cbs(&rdp->cblist)) { + rcu_barrier_trace(TPS("NQ"), cpu, rcu_state.barrier_sequence); continue; - if (rcu_segcblist_n_cbs(&rdp->cblist) && cpu_online(cpu)) { - rcu_barrier_trace(TPS("OnlineQ"), cpu, - rcu_state.barrier_sequence); + } + if (cpu_online(cpu)) { + rcu_barrier_trace(TPS("OnlineQ"), cpu, rcu_state.barrier_sequence); smp_call_function_single(cpu, rcu_barrier_func, (void *)cpu, 1); - } else if (rcu_segcblist_n_cbs(&rdp->cblist) && - cpu_is_offline(cpu)) { - rcu_barrier_trace(TPS("OfflineNoCBQ"), cpu, - rcu_state.barrier_sequence); + } else { + rcu_barrier_trace(TPS("OfflineNoCBQ"), cpu, rcu_state.barrier_sequence); local_irq_disable(); rcu_barrier_func((void *)cpu); local_irq_enable(); - } else if (cpu_is_offline(cpu)) { - rcu_barrier_trace(TPS("OfflineNoCBNoQ"), cpu, - rcu_state.barrier_sequence); - } else { - rcu_barrier_trace(TPS("OnlineNQ"), cpu, - rcu_state.barrier_sequence); } } cpus_read_unlock(); -- cgit v1.2.3