Commit 4b4399b2 authored by Zqiang's avatar Zqiang Committed by Paul E. McKenney
Browse files

rcu: Create per-cpu rcuc kthreads only when rcutree.use_softirq=0 



The per-CPU "rcuc" kthreads are used only by kernels booted with
rcutree.use_softirq=0, but they are nevertheless unconditionally created
by kernels built with CONFIG_RCU_BOOST=y.  This results in "rcuc"
kthreads being created that are never actually used.  This commit
therefore refrains from creating these kthreads unless the kernel
is actually booted with rcutree.use_softirq=0.

Acked-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarZqiang <qiang1.zhang@intel.com>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent eae9f147

kernel/rcu/tree.c

+1 −1
Original line number Diff line number Diff line
@@ -2894,7 +2894,7 @@ static int __init rcu_spawn_core_kthreads(void) 


	for_each_possible_cpu(cpu)

		per_cpu(rcu_data.rcu_cpu_has_work, cpu) = 0;

	if (!IS_ENABLED(CONFIG_RCU_BOOST) && use_softirq)

	if (use_softirq)

		return 0;

	WARN_ONCE(smpboot_register_percpu_thread(&rcu_cpu_thread_spec),

		  "%s: Could not start rcuc kthread, OOM is now expected behavior\n", __func__);