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