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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 default n
31 help
32 This option provides a kernel module that runs performance
33 tests on the RCU infrastructure. The kernel module may be built
34 after the fact on the running kernel to be tested, if desired.
35
36 Say Y here if you want RCU performance tests to be built into
37 the kernel.
38 Say M if you want the RCU performance tests to build as a module.
39 Say N if you are unsure.
40
41config RCU_TORTURE_TEST
42 tristate "torture tests for RCU"
43 depends on DEBUG_KERNEL
44 select TORTURE_TEST
45 default n
46 help
47 This option provides a kernel module that runs torture tests
48 on the RCU infrastructure. The kernel module may be built
49 after the fact on the running kernel to be tested, if desired.
50
51 Say Y here if you want RCU torture tests to be built into
52 the kernel.
53 Say M if you want the RCU torture tests to build as a module.
54 Say N if you are unsure.
55
56config RCU_REF_SCALE_TEST
57 tristate "Scalability tests for read-side synchronization (RCU and others)"
58 depends on DEBUG_KERNEL
59 select TORTURE_TEST
60 default n
61 help
62 This option provides a kernel module that runs performance tests
63 useful comparing RCU with various read-side synchronization mechanisms.
64 The kernel module may be built after the fact on the running kernel to be
65 tested, if desired.
66
67 Say Y here if you want these performance tests built into the kernel.
68 Say M if you want to build it as a module instead.
69 Say N if you are unsure.
70
71config RCU_CPU_STALL_TIMEOUT
72 int "RCU CPU stall timeout in seconds"
73 depends on RCU_STALL_COMMON
74 range 3 300
75 default 21
76 help
77 If a given RCU grace period extends more than the specified
78 number of seconds, a CPU stall warning is printed. If the
79 RCU grace period persists, additional CPU stall warnings are
80 printed at more widely spaced intervals.
81
82config RCU_EXP_CPU_STALL_TIMEOUT
83 int "Expedited RCU CPU stall timeout in milliseconds"
84 depends on RCU_STALL_COMMON
85 range 0 21000
86 default 0
87 help
88 If a given expedited RCU grace period extends more than the
89 specified number of milliseconds, a CPU stall warning is printed.
90 If the RCU grace period persists, additional CPU stall warnings
91 are printed at more widely spaced intervals. A value of zero
92 says to use the RCU_CPU_STALL_TIMEOUT value converted from
93 seconds to milliseconds.
94
95config RCU_TRACE
96 bool "Enable tracing for RCU"
97 depends on DEBUG_KERNEL
98 default y if TREE_RCU
99 select TRACE_CLOCK
100 help
101 This option enables additional tracepoints for ftrace-style
102 event tracing.
103
104 Say Y here if you want to enable RCU tracing
105 Say N if you are unsure.
106
107config RCU_EQS_DEBUG
108 bool "Provide debugging asserts for adding NO_HZ support to an arch"
109 depends on DEBUG_KERNEL
110 help
111 This option provides consistency checks in RCU's handling of
112 NO_HZ. These checks have proven quite helpful in detecting
113 bugs in arch-specific NO_HZ code.
114
115 Say N here if you need ultimate kernel/user switch latencies
116 Say Y if you are unsure
117
118config RCU_STRICT_GRACE_PERIOD
119 bool "Provide debug RCU implementation with short grace periods"
120 depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4 && !TINY_RCU
121 default n
122 select PREEMPT_COUNT if PREEMPT=n
123 help
124 Select this option to build an RCU variant that is strict about
125 grace periods, making them as short as it can. This limits
126 scalability, destroys real-time response, degrades battery
127 lifetime and kills performance. Don't try this on large
128 machines, as in systems with more than about 10 or 20 CPUs.
129 But in conjunction with tools like KASAN, it can be helpful
130 when looking for certain types of RCU usage bugs, for example,
131 too-short RCU read-side critical sections.
132
133endmenu # "RCU Debugging"
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"