@@ -168,10 +168,11 @@ CONFIG_RCU_EXP_CPU_STALL_TIMEOUT
Same as the CONFIG_RCU_CPU_STALL_TIMEOUT parameter but only for
the expedited grace period. This parameter defines the period
of time that RCU will wait from the beginning of an expedited
- grace period until it issues an RCU CPU stall warning. This time
- period is normally 20 milliseconds on Android devices. A zero
- value causes the CONFIG_RCU_CPU_STALL_TIMEOUT value to be used,
- after conversion to milliseconds.
+ grace period until it issues an RCU CPU stall warning.
+
+ A zero value causes the CONFIG_RCU_CPU_STALL_TIMEOUT value to be
+ used, after conversion to milliseconds, limited to a maximum of
+ 21 seconds.
This configuration parameter may be changed at runtime via the
/sys/module/rcupdate/parameters/rcu_exp_cpu_stall_timeout, however
@@ -93,7 +93,7 @@ config RCU_EXP_CPU_STALL_TIMEOUT
If the RCU grace period persists, additional CPU stall warnings
are printed at more widely spaced intervals. A value of zero
says to use the RCU_CPU_STALL_TIMEOUT value converted from
- seconds to milliseconds.
+ seconds to milliseconds, limited to a maximum of 21 seconds.
config RCU_TRACE
bool "Enable tracing for RCU"
Make the descriptions of CONFIG_EXT_RCU_CPU_STALL_TIMEOUT match the code: - there is no longer a default of 20 ms for Android since commit 1045a06724f3 ("remove CONFIG_ANDROID"), - the code includes a maximum of 21 seconds, evident when specifying 0 which means to use the CONFIG_RCU_STALL_TIMEOUT value (whose default is 60 seconds). Example .config: CONFIG_RCU_CPU_STALL_TIMEOUT=60 CONFIG_RCU_EXP_CPU_STALL_TIMEOUT=0 leads to: /sys/module/rcupdate/parameters/rcu_cpu_stall_timeout:60 /sys/module/rcupdate/parameters/rcu_exp_cpu_stall_timeout:21000 Fixes: 1045a06724f3 ("remove CONFIG_ANDROID") Signed-off-by: Robert Elliott <elliott@hpe.com> --- Documentation/RCU/stallwarn.rst | 9 +++++---- kernel/rcu/Kconfig.debug | 2 +- 2 files changed, 6 insertions(+), 5 deletions(-)