1# SPDX-License-Identifier: GPL-2.0-only
2#
3# RCU-related debugging configuration options
4#
5
6menu "RCU Debugging"
7
8config PROVE_RCU
9	def_bool PROVE_LOCKING
10
11config 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
22config TORTURE_TEST
23	tristate
24	default n
25
26config RCU_SCALE_TEST
27	tristate "performance tests for RCU"
28	depends on DEBUG_KERNEL
29	select TORTURE_TEST
30	select SRCU
31	select TASKS_RCU
32	select TASKS_RUDE_RCU
33	select TASKS_TRACE_RCU
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
45config 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
51	select TASKS_RUDE_RCU
52	select TASKS_TRACE_RCU
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
64config RCU_REF_SCALE_TEST
65	tristate "Scalability tests for read-side synchronization (RCU and others)"
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
83config 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
94config 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
106config 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
117config RCU_STRICT_GRACE_PERIOD
118	bool "Provide debug RCU implementation with short grace periods"
119	depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4
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
132endmenu # "RCU Debugging"
133