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