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 BOOTPARAM_RCU_STALL_PANIC 95 bool "Panic (Reboot) On RCU CPU stall timeout" 96 depends on RCU_STALL_COMMON 97 help 98 Say Y here to enable the kernel to panic on "rcu stall timeout", 99 which are bugs that RCU grace period extends more than 21 seconds 100 (configurable using the RCU_CPU_STALL_TIMEOUT). 101 102 The panic can be used in combination with panic_timeout, 103 to cause the system to reboot automatically after a 104 stall timeout. This feature is useful for high-availability 105 systems that have uptime guarantees and where a stall timeout 106 must be resolved ASAP. 107 108 Say N if unsure. 109 110config BOOTPARAM_RCU_STALL_PANIC_VALUE 111 int 112 depends on RCU_STALL_COMMON 113 range 0 1 114 default 0 if !BOOTPARAM_RCU_STALL_PANIC 115 default 1 if BOOTPARAM_RCU_STALL_PANIC 116 117config RCU_TRACE 118 bool "Enable tracing for RCU" 119 depends on DEBUG_KERNEL 120 default y if TREE_RCU 121 select TRACE_CLOCK 122 help 123 This option enables additional tracepoints for ftrace-style 124 event tracing. 125 126 Say Y here if you want to enable RCU tracing 127 Say N if you are unsure. 128 129config RCU_EQS_DEBUG 130 bool "Provide debugging asserts for adding NO_HZ support to an arch" 131 depends on DEBUG_KERNEL 132 help 133 This option provides consistency checks in RCU's handling of 134 NO_HZ. These checks have proven quite helpful in detecting 135 bugs in arch-specific NO_HZ code. 136 137 Say N here if you need ultimate kernel/user switch latencies 138 Say Y if you are unsure 139 140config RCU_STRICT_GRACE_PERIOD 141 bool "Provide debug RCU implementation with short grace periods" 142 depends on DEBUG_KERNEL && RCU_EXPERT 143 default n 144 select PREEMPT_COUNT if PREEMPT=n 145 help 146 Select this option to build an RCU variant that is strict about 147 grace periods, making them as short as it can. This limits 148 scalability, destroys real-time response, degrades battery 149 lifetime and kills performance. Don't try this on large 150 machines, as in systems with more than about 10 or 20 CPUs. 151 But in conjunction with tools like KASAN, it can be helpful 152 when looking for certain types of RCU usage bugs, for example, 153 too-short RCU read-side critical sections. 154 155endmenu # "RCU Debugging" 156