Kernels built with CONFIG_RCU_STRICT_GRACE_PERIOD=y can experience significant lock contention due to RCU's resulting focus on ending grace periods as soon as possible. This is OK, but only if there are not very many CPUs. This commit therefore puts this Kconfig option off-limits to systems with more than four CPUs. Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- kernel/rcu/Kconfig.debug | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug index 1942c1f1bb65..4fd64999300f 100644 --- a/kernel/rcu/Kconfig.debug +++ b/kernel/rcu/Kconfig.debug @@ -116,7 +116,7 @@ config RCU_EQS_DEBUG config RCU_STRICT_GRACE_PERIOD bool "Provide debug RCU implementation with short grace periods" - depends on DEBUG_KERNEL && RCU_EXPERT + depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4 default n select PREEMPT_COUNT if PREEMPT=n help -- 2.31.1.189.g2e36527f23
