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"