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1da177e4 LT |
1 | |
2 | config PRINTK_TIME | |
3 | bool "Show timing information on printks" | |
4 | help | |
5 | Selecting this option causes timing information to be | |
6 | included in printk output. This allows you to measure | |
7 | the interval between kernel operations, including bootup | |
8 | operations. This is useful for identifying long delays | |
9 | in kernel startup. | |
10 | ||
11 | ||
1da177e4 LT |
12 | config MAGIC_SYSRQ |
13 | bool "Magic SysRq key" | |
f346f4b3 | 14 | depends on !UML |
1da177e4 LT |
15 | help |
16 | If you say Y here, you will have some control over the system even | |
17 | if the system crashes for example during kernel debugging (e.g., you | |
18 | will be able to flush the buffer cache to disk, reboot the system | |
19 | immediately or dump some status information). This is accomplished | |
20 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
21 | also works on a serial console (on PC hardware at least), if you | |
22 | send a BREAK and then within 5 seconds a command keypress. The | |
23 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
24 | unless you really know what this hack does. | |
25 | ||
f346f4b3 AB |
26 | config DEBUG_KERNEL |
27 | bool "Kernel debugging" | |
28 | help | |
29 | Say Y here if you are developing drivers or trying to debug and | |
30 | identify kernel problems. | |
31 | ||
1da177e4 LT |
32 | config LOG_BUF_SHIFT |
33 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL | |
34 | range 12 21 | |
347a8dc3 | 35 | default 17 if S390 |
1da177e4 LT |
36 | default 16 if X86_NUMAQ || IA64 |
37 | default 15 if SMP | |
38 | default 14 | |
39 | help | |
40 | Select kernel log buffer size as a power of 2. | |
41 | Defaults and Examples: | |
42 | 17 => 128 KB for S/390 | |
43 | 16 => 64 KB for x86 NUMAQ or IA-64 | |
44 | 15 => 32 KB for SMP | |
45 | 14 => 16 KB for uniprocessor | |
46 | 13 => 8 KB | |
47 | 12 => 4 KB | |
48 | ||
8446f1d3 IM |
49 | config DETECT_SOFTLOCKUP |
50 | bool "Detect Soft Lockups" | |
51 | depends on DEBUG_KERNEL | |
52 | default y | |
53 | help | |
54 | Say Y here to enable the kernel to detect "soft lockups", | |
55 | which are bugs that cause the kernel to loop in kernel | |
56 | mode for more than 10 seconds, without giving other tasks a | |
57 | chance to run. | |
58 | ||
59 | When a soft-lockup is detected, the kernel will print the | |
60 | current stack trace (which you should report), but the | |
61 | system will stay locked up. This feature has negligible | |
62 | overhead. | |
63 | ||
64 | (Note that "hard lockups" are separate type of bugs that | |
65 | can be detected via the NMI-watchdog, on platforms that | |
66 | support it.) | |
67 | ||
1da177e4 LT |
68 | config SCHEDSTATS |
69 | bool "Collect scheduler statistics" | |
70 | depends on DEBUG_KERNEL && PROC_FS | |
71 | help | |
72 | If you say Y here, additional code will be inserted into the | |
73 | scheduler and related routines to collect statistics about | |
74 | scheduler behavior and provide them in /proc/schedstat. These | |
75 | stats may be useful for both tuning and debugging the scheduler | |
76 | If you aren't debugging the scheduler or trying to tune a specific | |
77 | application, you can say N to avoid the very slight overhead | |
78 | this adds. | |
79 | ||
80 | config DEBUG_SLAB | |
4a2f0acf | 81 | bool "Debug slab memory allocations" |
50dd26ba | 82 | depends on DEBUG_KERNEL && SLAB |
1da177e4 LT |
83 | help |
84 | Say Y here to have the kernel do limited verification on memory | |
85 | allocation as well as poisoning memory on free to catch use of freed | |
86 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
87 | ||
871751e2 AV |
88 | config DEBUG_SLAB_LEAK |
89 | bool "Memory leak debugging" | |
90 | depends on DEBUG_SLAB | |
91 | ||
1da177e4 LT |
92 | config DEBUG_PREEMPT |
93 | bool "Debug preemptible kernel" | |
94 | depends on DEBUG_KERNEL && PREEMPT | |
95 | default y | |
96 | help | |
97 | If you say Y here then the kernel will use a debug variant of the | |
98 | commonly used smp_processor_id() function and will print warnings | |
99 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
100 | will detect preemption count underflows. | |
101 | ||
408894ee IM |
102 | config DEBUG_MUTEXES |
103 | bool "Mutex debugging, deadlock detection" | |
cca57c5b | 104 | default n |
408894ee IM |
105 | depends on DEBUG_KERNEL |
106 | help | |
107 | This allows mutex semantics violations and mutex related deadlocks | |
108 | (lockups) to be detected and reported automatically. | |
109 | ||
1da177e4 LT |
110 | config DEBUG_SPINLOCK |
111 | bool "Spinlock debugging" | |
112 | depends on DEBUG_KERNEL | |
113 | help | |
114 | Say Y here and build SMP to catch missing spinlock initialization | |
115 | and certain other kinds of spinlock errors commonly made. This is | |
116 | best used in conjunction with the NMI watchdog so that spinlock | |
117 | deadlocks are also debuggable. | |
118 | ||
119 | config DEBUG_SPINLOCK_SLEEP | |
120 | bool "Sleep-inside-spinlock checking" | |
121 | depends on DEBUG_KERNEL | |
122 | help | |
123 | If you say Y here, various routines which may sleep will become very | |
124 | noisy if they are called with a spinlock held. | |
125 | ||
126 | config DEBUG_KOBJECT | |
127 | bool "kobject debugging" | |
128 | depends on DEBUG_KERNEL | |
129 | help | |
130 | If you say Y here, some extra kobject debugging messages will be sent | |
131 | to the syslog. | |
132 | ||
133 | config DEBUG_HIGHMEM | |
134 | bool "Highmem debugging" | |
135 | depends on DEBUG_KERNEL && HIGHMEM | |
136 | help | |
137 | This options enables addition error checking for high memory systems. | |
138 | Disable for production systems. | |
139 | ||
140 | config DEBUG_BUGVERBOSE | |
141 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED | |
c8538a7a | 142 | depends on BUG |
0d078f6f | 143 | depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV |
1da177e4 LT |
144 | default !EMBEDDED |
145 | help | |
146 | Say Y here to make BUG() panics output the file name and line number | |
147 | of the BUG call as well as the EIP and oops trace. This aids | |
148 | debugging but costs about 70-100K of memory. | |
149 | ||
150 | config DEBUG_INFO | |
151 | bool "Compile the kernel with debug info" | |
152 | depends on DEBUG_KERNEL | |
153 | help | |
154 | If you say Y here the resulting kernel image will include | |
155 | debugging info resulting in a larger kernel image. | |
156 | Say Y here only if you plan to debug the kernel. | |
157 | ||
158 | If unsure, say N. | |
159 | ||
1da177e4 LT |
160 | config DEBUG_FS |
161 | bool "Debug Filesystem" | |
ae36b883 | 162 | depends on SYSFS |
1da177e4 LT |
163 | help |
164 | debugfs is a virtual file system that kernel developers use to put | |
165 | debugging files into. Enable this option to be able to read and | |
166 | write to these files. | |
167 | ||
168 | If unsure, say N. | |
169 | ||
a241ec65 PM |
170 | config DEBUG_VM |
171 | bool "Debug VM" | |
172 | depends on DEBUG_KERNEL | |
173 | help | |
13e7444b NP |
174 | Enable this to turn on extended checks in the virtual-memory system |
175 | that may impact performance. | |
a241ec65 PM |
176 | |
177 | If unsure, say N. | |
178 | ||
1da177e4 LT |
179 | config FRAME_POINTER |
180 | bool "Compile the kernel with frame pointers" | |
aeb39986 | 181 | depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML) |
37fce857 | 182 | default y if DEBUG_INFO && UML |
1da177e4 LT |
183 | help |
184 | If you say Y here the resulting kernel image will be slightly larger | |
2a38bccd JJ |
185 | and slower, but it might give very useful debugging information on |
186 | some architectures or if you use external debuggers. | |
aeb39986 | 187 | If you don't debug the kernel, you can say N. |
1da177e4 | 188 | |
604bf5a2 JB |
189 | config UNWIND_INFO |
190 | bool "Compile the kernel with frame unwind information" | |
191 | depends on !IA64 | |
06a1be16 | 192 | depends on !MODULES || !(MIPS || PARISC || PPC || SUPERH || V850) |
604bf5a2 JB |
193 | help |
194 | If you say Y here the resulting kernel image will be slightly larger | |
195 | but not slower, and it will give very useful debugging information. | |
196 | If you don't debug the kernel, you can say N, but we may not be able | |
197 | to solve problems without frame unwind information or frame pointers. | |
198 | ||
a9df3d0f IM |
199 | config FORCED_INLINING |
200 | bool "Force gcc to inline functions marked 'inline'" | |
201 | depends on DEBUG_KERNEL | |
202 | default y | |
203 | help | |
204 | This option determines if the kernel forces gcc to inline the functions | |
205 | developers have marked 'inline'. Doing so takes away freedom from gcc to | |
206 | do what it thinks is best, which is desirable for the gcc 3.x series of | |
207 | compilers. The gcc 4.x series have a rewritten inlining algorithm and | |
208 | disabling this option will generate a smaller kernel there. Hopefully | |
209 | this algorithm is so good that allowing gcc4 to make the decision can | |
210 | become the default in the future, until then this option is there to | |
211 | test gcc for this. | |
212 | ||
a241ec65 PM |
213 | config RCU_TORTURE_TEST |
214 | tristate "torture tests for RCU" | |
215 | depends on DEBUG_KERNEL | |
216 | default n | |
217 | help | |
218 | This option provides a kernel module that runs torture tests | |
219 | on the RCU infrastructure. The kernel module may be built | |
220 | after the fact on the running kernel to be tested, if desired. | |
221 | ||
222 | Say Y here if you want RCU torture tests to start automatically | |
223 | at boot time (you probably don't). | |
224 | Say M if you want the RCU torture tests to build as a module. | |
225 | Say N if you are unsure. |