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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 | ||
12 | config DEBUG_KERNEL | |
13 | bool "Kernel debugging" | |
14 | help | |
15 | Say Y here if you are developing drivers or trying to debug and | |
16 | identify kernel problems. | |
17 | ||
18 | config MAGIC_SYSRQ | |
19 | bool "Magic SysRq key" | |
20 | depends on DEBUG_KERNEL && !UML | |
21 | help | |
22 | If you say Y here, you will have some control over the system even | |
23 | if the system crashes for example during kernel debugging (e.g., you | |
24 | will be able to flush the buffer cache to disk, reboot the system | |
25 | immediately or dump some status information). This is accomplished | |
26 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
27 | also works on a serial console (on PC hardware at least), if you | |
28 | send a BREAK and then within 5 seconds a command keypress. The | |
29 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
30 | unless you really know what this hack does. | |
31 | ||
32 | config LOG_BUF_SHIFT | |
33 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL | |
34 | range 12 21 | |
35 | default 17 if ARCH_S390 | |
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 | |
81 | bool "Debug memory allocations" | |
82 | depends on DEBUG_KERNEL | |
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 | ||
88 | config DEBUG_PREEMPT | |
89 | bool "Debug preemptible kernel" | |
90 | depends on DEBUG_KERNEL && PREEMPT | |
91 | default y | |
92 | help | |
93 | If you say Y here then the kernel will use a debug variant of the | |
94 | commonly used smp_processor_id() function and will print warnings | |
95 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
96 | will detect preemption count underflows. | |
97 | ||
98 | config DEBUG_SPINLOCK | |
99 | bool "Spinlock debugging" | |
100 | depends on DEBUG_KERNEL | |
101 | help | |
102 | Say Y here and build SMP to catch missing spinlock initialization | |
103 | and certain other kinds of spinlock errors commonly made. This is | |
104 | best used in conjunction with the NMI watchdog so that spinlock | |
105 | deadlocks are also debuggable. | |
106 | ||
107 | config DEBUG_SPINLOCK_SLEEP | |
108 | bool "Sleep-inside-spinlock checking" | |
109 | depends on DEBUG_KERNEL | |
110 | help | |
111 | If you say Y here, various routines which may sleep will become very | |
112 | noisy if they are called with a spinlock held. | |
113 | ||
114 | config DEBUG_KOBJECT | |
115 | bool "kobject debugging" | |
116 | depends on DEBUG_KERNEL | |
117 | help | |
118 | If you say Y here, some extra kobject debugging messages will be sent | |
119 | to the syslog. | |
120 | ||
121 | config DEBUG_HIGHMEM | |
122 | bool "Highmem debugging" | |
123 | depends on DEBUG_KERNEL && HIGHMEM | |
124 | help | |
125 | This options enables addition error checking for high memory systems. | |
126 | Disable for production systems. | |
127 | ||
128 | config DEBUG_BUGVERBOSE | |
129 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED | |
c8538a7a | 130 | depends on BUG |
0d078f6f | 131 | depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV |
1da177e4 LT |
132 | default !EMBEDDED |
133 | help | |
134 | Say Y here to make BUG() panics output the file name and line number | |
135 | of the BUG call as well as the EIP and oops trace. This aids | |
136 | debugging but costs about 70-100K of memory. | |
137 | ||
138 | config DEBUG_INFO | |
139 | bool "Compile the kernel with debug info" | |
140 | depends on DEBUG_KERNEL | |
141 | help | |
142 | If you say Y here the resulting kernel image will include | |
143 | debugging info resulting in a larger kernel image. | |
144 | Say Y here only if you plan to debug the kernel. | |
145 | ||
146 | If unsure, say N. | |
147 | ||
148 | config DEBUG_IOREMAP | |
149 | bool "Enable ioremap() debugging" | |
150 | depends on DEBUG_KERNEL && PARISC | |
151 | help | |
152 | Enabling this option will cause the kernel to distinguish between | |
153 | ioremapped and physical addresses. It will print a backtrace (at | |
154 | most one every 10 seconds), hopefully allowing you to see which | |
155 | drivers need work. Fixing all these problems is a prerequisite | |
156 | for turning on USE_HPPA_IOREMAP. The warnings are harmless; | |
157 | the kernel has enough information to fix the broken drivers | |
158 | automatically, but we'd like to make it more efficient by not | |
159 | having to do that. | |
160 | ||
161 | config DEBUG_FS | |
162 | bool "Debug Filesystem" | |
3348e05a | 163 | depends on DEBUG_KERNEL && SYSFS |
1da177e4 LT |
164 | help |
165 | debugfs is a virtual file system that kernel developers use to put | |
166 | debugging files into. Enable this option to be able to read and | |
167 | write to these files. | |
168 | ||
169 | If unsure, say N. | |
170 | ||
171 | config FRAME_POINTER | |
172 | bool "Compile the kernel with frame pointers" | |
aeb39986 | 173 | depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML) |
37fce857 | 174 | default y if DEBUG_INFO && UML |
1da177e4 LT |
175 | help |
176 | If you say Y here the resulting kernel image will be slightly larger | |
2a38bccd JJ |
177 | and slower, but it might give very useful debugging information on |
178 | some architectures or if you use external debuggers. | |
aeb39986 | 179 | If you don't debug the kernel, you can say N. |
1da177e4 | 180 |