[mirror_ubuntu-kernels.git] / kernel / rcu / Kconfig.debug

# 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
	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
	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
	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 RCU_EXP_CPU_STALL_TIMEOUT
	int "Expedited RCU CPU stall timeout in milliseconds"
	depends on RCU_STALL_COMMON
	range 0 21000
	default 0
	help
	  If a given expedited RCU grace period extends more than the
	  specified number of milliseconds, a CPU stall warning is printed.
	  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.

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 && NR_CPUS <= 4 && !TINY_RCU
	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"
Commit	Line	Data
ec8f24b7	1	# SPDX-License-Identifier: GPL-2.0-only
43a0a2a7 PM	2	#
	3	# RCU-related debugging configuration options
	4	#
	5
	6	menu "RCU Debugging"
	7
	8	config PROVE_RCU
	9	def_bool PROVE_LOCKING
	10
28875945 JFG	11	config PROVE_RCU_LIST
	12	bool "RCU list lockdep debugging"
	13	depends on PROVE_RCU && RCU_EXPERT
	14	default n
	15	help
	16	Enable RCU lockdep checking for list usages. By default it is
	17	turned off since there are several list RCU users that still
	18	need to be converted to pass a lockdep expression. To prevent
	19	false-positive splats, we keep it default disabled but once all
	20	users are converted, we can remove this config option.
	21
43a0a2a7 PM	22	config TORTURE_TEST
	23	tristate
	24	default n
	25
4e88ec4a	26	config RCU_SCALE_TEST
43a0a2a7 PM	27	tristate "performance tests for RCU"
	28	depends on DEBUG_KERNEL
	29	select TORTURE_TEST
	30	select SRCU
43a0a2a7 PM	31	default n
	32	help
	33	This option provides a kernel module that runs performance
	34	tests on the RCU infrastructure. The kernel module may be built
	35	after the fact on the running kernel to be tested, if desired.
	36
	37	Say Y here if you want RCU performance tests to be built into
	38	the kernel.
	39	Say M if you want the RCU performance tests to build as a module.
	40	Say N if you are unsure.
	41
	42	config RCU_TORTURE_TEST
	43	tristate "torture tests for RCU"
	44	depends on DEBUG_KERNEL
	45	select TORTURE_TEST
	46	select SRCU
43a0a2a7 PM	47	default n
	48	help
	49	This option provides a kernel module that runs torture tests
	50	on the RCU infrastructure. The kernel module may be built
	51	after the fact on the running kernel to be tested, if desired.
	52
	53	Say Y here if you want RCU torture tests to be built into
	54	the kernel.
	55	Say M if you want the RCU torture tests to build as a module.
	56	Say N if you are unsure.
	57
8e4ec3d0 PM	58	config RCU_REF_SCALE_TEST
8e4ec3d0 PM	59	tristate "Scalability tests for read-side synchronization (RCU and others)"
653ed64b JFG	60	depends on DEBUG_KERNEL
	61	select TORTURE_TEST
	62	select SRCU
653ed64b JFG	63	default n
	64	help
	65	This option provides a kernel module that runs performance tests
	66	useful comparing RCU with various read-side synchronization mechanisms.
	67	The kernel module may be built after the fact on the running kernel to be
	68	tested, if desired.
	69
	70	Say Y here if you want these performance tests built into the kernel.
	71	Say M if you want to build it as a module instead.
	72	Say N if you are unsure.
	73
43a0a2a7 PM	74	config RCU_CPU_STALL_TIMEOUT
	75	int "RCU CPU stall timeout in seconds"
	76	depends on RCU_STALL_COMMON
	77	range 3 300
	78	default 21
	79	help
	80	If a given RCU grace period extends more than the specified
	81	number of seconds, a CPU stall warning is printed. If the
	82	RCU grace period persists, additional CPU stall warnings are
	83	printed at more widely spaced intervals.
	84
28b3ae42 UR	85	config RCU_EXP_CPU_STALL_TIMEOUT
	86	int "Expedited RCU CPU stall timeout in milliseconds"
	87	depends on RCU_STALL_COMMON
	88	range 0 21000
1045a067	89	default 0
28b3ae42 UR	90	help
	91	If a given expedited RCU grace period extends more than the
	92	specified number of milliseconds, a CPU stall warning is printed.
	93	If the RCU grace period persists, additional CPU stall warnings
	94	are printed at more widely spaced intervals. A value of zero
	95	says to use the RCU_CPU_STALL_TIMEOUT value converted from
	96	seconds to milliseconds.
	97
43a0a2a7 PM	98	config RCU_TRACE
	99	bool "Enable tracing for RCU"
	100	depends on DEBUG_KERNEL
	101	default y if TREE_RCU
	102	select TRACE_CLOCK
	103	help
	104	This option enables additional tracepoints for ftrace-style
	105	event tracing.
	106
	107	Say Y here if you want to enable RCU tracing
	108	Say N if you are unsure.
	109
	110	config RCU_EQS_DEBUG
	111	bool "Provide debugging asserts for adding NO_HZ support to an arch"
	112	depends on DEBUG_KERNEL
	113	help
	114	This option provides consistency checks in RCU's handling of
	115	NO_HZ. These checks have proven quite helpful in detecting
	116	bugs in arch-specific NO_HZ code.
	117
	118	Say N here if you need ultimate kernel/user switch latencies
	119	Say Y if you are unsure
	120
8cbd0e38 PM	121	config RCU_STRICT_GRACE_PERIOD
8cbd0e38 PM	122	bool "Provide debug RCU implementation with short grace periods"
b3ade95b	123	depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4 && !TINY_RCU
8cbd0e38 PM	124	default n
	125	select PREEMPT_COUNT if PREEMPT=n
	126	help
	127	Select this option to build an RCU variant that is strict about
	128	grace periods, making them as short as it can. This limits
	129	scalability, destroys real-time response, degrades battery
	130	lifetime and kills performance. Don't try this on large
	131	machines, as in systems with more than about 10 or 20 CPUs.
	132	But in conjunction with tools like KASAN, it can be helpful
	133	when looking for certain types of RCU usage bugs, for example,
	134	too-short RCU read-side critical sections.
	135
43a0a2a7	136	endmenu # "RCU Debugging"