# SPDX-License-Identifier: GPL-2.0-only
|
#
|
# RCU-related debugging configuration options
|
#
|
|
menu "RCU Debugging"
|
|
config PROVE_RCU
|
def_bool PROVE_LOCKING
|
|
config PROVE_RCU_LIST
|
bool "RCU list lockdep debugging"
|
depends on PROVE_RCU && RCU_EXPERT
|
default n
|
help
|
Enable RCU lockdep checking for list usages. By default it is
|
turned off since there are several list RCU users that still
|
need to be converted to pass a lockdep expression. To prevent
|
false-positive splats, we keep it default disabled but once all
|
users are converted, we can remove this config option.
|
|
config TORTURE_TEST
|
tristate
|
default n
|
|
config RCU_SCALE_TEST
|
tristate "performance tests for RCU"
|
depends on DEBUG_KERNEL
|
select TORTURE_TEST
|
select SRCU
|
select TASKS_RCU
|
select TASKS_RUDE_RCU
|
select TASKS_TRACE_RCU
|
default n
|
help
|
This option provides a kernel module that runs performance
|
tests on the RCU infrastructure. The kernel module may be built
|
after the fact on the running kernel to be tested, if desired.
|
|
Say Y here if you want RCU performance tests to be built into
|
the kernel.
|
Say M if you want the RCU performance tests to build as a module.
|
Say N if you are unsure.
|
|
config RCU_TORTURE_TEST
|
tristate "torture tests for RCU"
|
depends on DEBUG_KERNEL
|
select TORTURE_TEST
|
select SRCU
|
select TASKS_RCU
|
select TASKS_RUDE_RCU
|
select TASKS_TRACE_RCU
|
default n
|
help
|
This option provides a kernel module that runs torture tests
|
on the RCU infrastructure. The kernel module may be built
|
after the fact on the running kernel to be tested, if desired.
|
|
Say Y here if you want RCU torture tests to be built into
|
the kernel.
|
Say M if you want the RCU torture tests to build as a module.
|
Say N if you are unsure.
|
|
config RCU_REF_SCALE_TEST
|
tristate "Scalability tests for read-side synchronization (RCU and others)"
|
depends on DEBUG_KERNEL
|
select TORTURE_TEST
|
select SRCU
|
select TASKS_RCU
|
select TASKS_RUDE_RCU
|
select TASKS_TRACE_RCU
|
default n
|
help
|
This option provides a kernel module that runs performance tests
|
useful comparing RCU with various read-side synchronization mechanisms.
|
The kernel module may be built after the fact on the running kernel to be
|
tested, if desired.
|
|
Say Y here if you want these performance tests built into the kernel.
|
Say M if you want to build it as a module instead.
|
Say N if you are unsure.
|
|
config RCU_CPU_STALL_TIMEOUT
|
int "RCU CPU stall timeout in seconds"
|
depends on RCU_STALL_COMMON
|
range 3 300
|
default 21
|
help
|
If a given RCU grace period extends more than the specified
|
number of seconds, a CPU stall warning is printed. If the
|
RCU grace period persists, additional CPU stall warnings are
|
printed at more widely spaced intervals.
|
|
config BOOTPARAM_RCU_STALL_PANIC
|
bool "Panic (Reboot) On RCU CPU stall timeout"
|
depends on RCU_STALL_COMMON
|
help
|
Say Y here to enable the kernel to panic on "rcu stall timeout",
|
which are bugs that RCU grace period extends more than 21 seconds
|
(configurable using the RCU_CPU_STALL_TIMEOUT).
|
|
The panic can be used in combination with panic_timeout,
|
to cause the system to reboot automatically after a
|
stall timeout. This feature is useful for high-availability
|
systems that have uptime guarantees and where a stall timeout
|
must be resolved ASAP.
|
|
Say N if unsure.
|
|
config BOOTPARAM_RCU_STALL_PANIC_VALUE
|
int
|
depends on RCU_STALL_COMMON
|
range 0 1
|
default 0 if !BOOTPARAM_RCU_STALL_PANIC
|
default 1 if BOOTPARAM_RCU_STALL_PANIC
|
|
config RCU_TRACE
|
bool "Enable tracing for RCU"
|
depends on DEBUG_KERNEL
|
default y if TREE_RCU
|
select TRACE_CLOCK
|
help
|
This option enables additional tracepoints for ftrace-style
|
event tracing.
|
|
Say Y here if you want to enable RCU tracing
|
Say N if you are unsure.
|
|
config RCU_EQS_DEBUG
|
bool "Provide debugging asserts for adding NO_HZ support to an arch"
|
depends on DEBUG_KERNEL
|
help
|
This option provides consistency checks in RCU's handling of
|
NO_HZ. These checks have proven quite helpful in detecting
|
bugs in arch-specific NO_HZ code.
|
|
Say N here if you need ultimate kernel/user switch latencies
|
Say Y if you are unsure
|
|
config RCU_STRICT_GRACE_PERIOD
|
bool "Provide debug RCU implementation with short grace periods"
|
depends on DEBUG_KERNEL && RCU_EXPERT
|
default n
|
select PREEMPT_COUNT if PREEMPT=n
|
help
|
Select this option to build an RCU variant that is strict about
|
grace periods, making them as short as it can. This limits
|
scalability, destroys real-time response, degrades battery
|
lifetime and kills performance. Don't try this on large
|
machines, as in systems with more than about 10 or 20 CPUs.
|
But in conjunction with tools like KASAN, it can be helpful
|
when looking for certain types of RCU usage bugs, for example,
|
too-short RCU read-side critical sections.
|
|
endmenu # "RCU Debugging"
|
