Commit 81a208c5 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Boqun Feng
Browse files

rcu: Clarify RCU_LAZY and RCU_LAZY_DEFAULT_OFF help text 



This commit wordsmiths the RCU_LAZY and RCU_LAZY_DEFAULT_OFF Kconfig
options' help text.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarBoqun Feng <boqun.feng@gmail.com>
parent 053ca725

kernel/rcu/Kconfig

+13 −7
Original line number Diff line number Diff line
@@ -323,21 +323,27 @@ config RCU_LAZY 
	depends on RCU_NOCB_CPU

	default n

	help

	  To save power, batch RCU callbacks and flush after delay, memory

	  pressure, or callback list growing too big.

	  To save power, batch RCU callbacks and delay starting the

	  corresponding grace  period for multiple seconds.  The grace

	  period will be started after this delay, in case of memory

	  pressure, or if the corresponding CPU's callback list grows

	  too large.



	  Requires rcu_nocbs=all to be set.

	  These delays happen only on rcu_nocbs CPUs, that is, CPUs

	  whose callbacks have been offloaded.



	  Use rcutree.enable_rcu_lazy=0 to turn it off at boot time.

	  Use the rcutree.enable_rcu_lazy=0 kernel-boot parameter to

	  globally disable these delays.



config RCU_LAZY_DEFAULT_OFF

	bool "Turn RCU lazy invocation off by default"

	depends on RCU_LAZY

	default n

	help

	  Allows building the kernel with CONFIG_RCU_LAZY=y yet keep it default

	  off. Boot time param rcutree.enable_rcu_lazy=1 can be used to switch

	  it back on.

	  Build the kernel with CONFIG_RCU_LAZY=y, but cause the kernel

	  to boot with these energy-efficiency delays disabled.  Use the

	  rcutree.enable_rcu_lazy=0 kernel-boot parameter to override

	  the this option at boot time, thus re-enabling these delays.



config RCU_DOUBLE_CHECK_CB_TIME

	bool "RCU callback-batch backup time check"