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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2020-12-15 17:16:45 +0300
committerPaul E. McKenney <paulmck@kernel.org>2021-01-05 00:43:50 +0300
commit2341bc4a0311e4319ced6c2828bb19309dee74fd (patch)
treeaf32b8028f1d91efe6ca53421b344aa338daf5e1 /kernel/rcu
parent5c8fe583cce542aa0b84adc939ce85293de36e5e (diff)
downloadlinux-2341bc4a0311e4319ced6c2828bb19309dee74fd.tar.xz
rcu: Make RCU_BOOST default on CONFIG_PREEMPT_RT
On PREEMPT_RT kernels, RCU callbacks are deferred to the `rcuc' kthread. This can stall RCU grace periods due to lengthy preemption not only of RCU readers but also of 'rcuc' kthreads, either of which prevent grace periods from completing, which can in turn result in OOM. Because PREEMPT_RT kernels have more kthreads that can block grace periods, it is more important for such kernels to enable RCU_BOOST. This commit therefore makes RCU_BOOST the default on PREEMPT_RT. RCU_BOOST can still be manually disabled if need be. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/Kconfig4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index cdc57b4f6d48..aa8cc8c977e7 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -188,8 +188,8 @@ config RCU_FAST_NO_HZ
config RCU_BOOST
bool "Enable RCU priority boosting"
- depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
- default n
+ depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT
+ default y if PREEMPT_RT
help
This option boosts the priority of preempted RCU readers that
block the current preemptible RCU grace period for too long.