[linux.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
	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 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"
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
	31	select TASKS_RCU
3d6e43c7	32	select TASKS_RUDE_RCU
c1a76c0b	33	select TASKS_TRACE_RCU
43a0a2a7 PM	34	default n
	35	help
	36	This option provides a kernel module that runs performance
	37	tests on the RCU infrastructure. The kernel module may be built
	38	after the fact on the running kernel to be tested, if desired.
	39
	40	Say Y here if you want RCU performance tests to be built into
	41	the kernel.
	42	Say M if you want the RCU performance tests to build as a module.
	43	Say N if you are unsure.
	44
	45	config RCU_TORTURE_TEST
	46	tristate "torture tests for RCU"
	47	depends on DEBUG_KERNEL
	48	select TORTURE_TEST
	49	select SRCU
	50	select TASKS_RCU
3d6e43c7	51	select TASKS_RUDE_RCU
c1a76c0b	52	select TASKS_TRACE_RCU
43a0a2a7 PM	53	default n
	54	help
	55	This option provides a kernel module that runs torture tests
	56	on the RCU infrastructure. The kernel module may be built
	57	after the fact on the running kernel to be tested, if desired.
	58
	59	Say Y here if you want RCU torture tests to be built into
	60	the kernel.
	61	Say M if you want the RCU torture tests to build as a module.
	62	Say N if you are unsure.
	63
8e4ec3d0 PM	64	config RCU_REF_SCALE_TEST
8e4ec3d0 PM	65	tristate "Scalability tests for read-side synchronization (RCU and others)"
653ed64b JFG	66	depends on DEBUG_KERNEL
	67	select TORTURE_TEST
	68	select SRCU
	69	select TASKS_RCU
	70	select TASKS_RUDE_RCU
	71	select TASKS_TRACE_RCU
	72	default n
	73	help
	74	This option provides a kernel module that runs performance tests
	75	useful comparing RCU with various read-side synchronization mechanisms.
	76	The kernel module may be built after the fact on the running kernel to be
	77	tested, if desired.
	78
	79	Say Y here if you want these performance tests built into the kernel.
	80	Say M if you want to build it as a module instead.
	81	Say N if you are unsure.
	82
43a0a2a7 PM	83	config RCU_CPU_STALL_TIMEOUT
	84	int "RCU CPU stall timeout in seconds"
	85	depends on RCU_STALL_COMMON
	86	range 3 300
	87	default 21
	88	help
	89	If a given RCU grace period extends more than the specified
	90	number of seconds, a CPU stall warning is printed. If the
	91	RCU grace period persists, additional CPU stall warnings are
	92	printed at more widely spaced intervals.
	93
	94	config RCU_TRACE
	95	bool "Enable tracing for RCU"
	96	depends on DEBUG_KERNEL
	97	default y if TREE_RCU
	98	select TRACE_CLOCK
	99	help
	100	This option enables additional tracepoints for ftrace-style
	101	event tracing.
	102
	103	Say Y here if you want to enable RCU tracing
	104	Say N if you are unsure.
	105
	106	config RCU_EQS_DEBUG
	107	bool "Provide debugging asserts for adding NO_HZ support to an arch"
	108	depends on DEBUG_KERNEL
	109	help
	110	This option provides consistency checks in RCU's handling of
	111	NO_HZ. These checks have proven quite helpful in detecting
	112	bugs in arch-specific NO_HZ code.
	113
	114	Say N here if you need ultimate kernel/user switch latencies
	115	Say Y if you are unsure
	116
8cbd0e38 PM	117	config RCU_STRICT_GRACE_PERIOD
	118	bool "Provide debug RCU implementation with short grace periods"
	119	depends on DEBUG_KERNEL && RCU_EXPERT
	120	default n
	121	select PREEMPT_COUNT if PREEMPT=n
	122	help
	123	Select this option to build an RCU variant that is strict about
	124	grace periods, making them as short as it can. This limits
	125	scalability, destroys real-time response, degrades battery
	126	lifetime and kills performance. Don't try this on large
	127	machines, as in systems with more than about 10 or 20 CPUs.
	128	But in conjunction with tools like KASAN, it can be helpful
	129	when looking for certain types of RCU usage bugs, for example,
	130	too-short RCU read-side critical sections.
	131
43a0a2a7	132	endmenu # "RCU Debugging"