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| author | Paul E. McKenney <paulmck@kernel.org> | 2021-09-27 14:18:51 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-11-30 17:24:47 -0800 |
| commit | e2c73a6860bdf54f2c6bf8cddc34ddc91a1343e1 (patch) | |
| tree | d8b4e1ad9c9a7131bfe6fe50235e4d66465364cc /kernel/rcu/Kconfig | |
| parent | 24eab6e1ff58d33048c36b5452f5d284c3710d02 (diff) | |
| download | linux-e2c73a6860bdf54f2c6bf8cddc34ddc91a1343e1.tar.gz linux-e2c73a6860bdf54f2c6bf8cddc34ddc91a1343e1.tar.bz2 linux-e2c73a6860bdf54f2c6bf8cddc34ddc91a1343e1.zip | |
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/Kconfig | 18 |
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 |