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