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| author | Paul E. McKenney <paulmck@kernel.org> | 2025-01-09 06:50:37 +0300 |
|---|---|---|
| committer | Boqun Feng <boqun.feng@gmail.com> | 2025-02-05 08:50:06 +0300 |
| commit | 81a208c56ef6a07cfde338603e891cc647b73d21 (patch) | |
| tree | c3e51096afa0e1ef1bc632055ecfb4ab8c544aff | |
| parent | 053ca72554df6923d703a1c072f1930e1870b040 (diff) | |
| download | linux-81a208c56ef6a07cfde338603e891cc647b73d21.tar.xz | |
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: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
| -rw-r--r-- | kernel/rcu/Kconfig | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig index b9b6bc55185d..2bb22dac3b5a 100644 --- a/kernel/rcu/Kconfig +++ b/kernel/rcu/Kconfig @@ -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" |