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authorPaul E. McKenney <paulmck@kernel.org>2021-09-28 00:18:51 +0300
committerPaul E. McKenney <paulmck@kernel.org>2021-12-01 04:24:47 +0300
commite2c73a6860bdf54f2c6bf8cddc34ddc91a1343e1 (patch)
treed8b4e1ad9c9a7131bfe6fe50235e4d66465364cc /kernel/rcu/Kconfig
parent24eab6e1ff58d33048c36b5452f5d284c3710d02 (diff)
downloadlinux-e2c73a6860bdf54f2c6bf8cddc34ddc91a1343e1.tar.xz
rcu: Remove the RCU_FAST_NO_HZ Kconfig option
All of the uses of CONFIG_RCU_FAST_NO_HZ=y that I have seen involve systems with RCU callbacks offloaded. In this situation, all that this Kconfig option does is slow down idle entry/exit with an additional allways-taken early exit. If this is the only use case, then this Kconfig option nothing but an attractive nuisance that needs to go away. This commit therefore removes the RCU_FAST_NO_HZ Kconfig option. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/Kconfig')
-rw-r--r--kernel/rcu/Kconfig18
1 files changed, 0 insertions, 18 deletions
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index 3128b7cf8e1f..4005f2728f1a 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -169,24 +169,6 @@ config RCU_FANOUT_LEAF
Take the default if unsure.
-config RCU_FAST_NO_HZ
- bool "Accelerate last non-dyntick-idle CPU's grace periods"
- depends on NO_HZ_COMMON && SMP && RCU_EXPERT
- default n
- help
- This option permits CPUs to enter dynticks-idle state even if
- they have RCU callbacks queued, and prevents RCU from waking
- these CPUs up more than roughly once every four jiffies (by
- default, you can adjust this using the rcutree.rcu_idle_gp_delay
- parameter), thus improving energy efficiency. On the other
- hand, this option increases the duration of RCU grace periods,
- for example, slowing down synchronize_rcu().
-
- Say Y if energy efficiency is critically important, and you
- don't care about increased grace-period durations.
-
- Say N if you are unsure.
-
config RCU_BOOST
bool "Enable RCU priority boosting"
depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT