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Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2config 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070012config MAGIC_SYSRQ
13 bool "Magic SysRq key"
Adrian Bunkf346f4b2006-01-09 20:54:51 -080014 depends on !UML
Linus Torvalds1da177e2005-04-16 15:20:36 -070015 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
Adrian Bunkf346f4b2006-01-09 20:54:51 -080026config 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070032config LOG_BUF_SHIFT
33 int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
34 range 12 21
Martin Schwidefsky347a8dc2006-01-06 00:19:28 -080035 default 17 if S390
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 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
Ingo Molnar8446f1d2005-09-06 15:16:27 -070049config 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070068config 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
80config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -080081 bool "Debug slab memory allocations"
Ingo Molnar50dd26b2006-01-08 01:01:42 -080082 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 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
Al Viro871751e2006-03-25 03:06:39 -080088config DEBUG_SLAB_LEAK
89 bool "Memory leak debugging"
90 depends on DEBUG_SLAB
91
Linus Torvalds1da177e2005-04-16 15:20:36 -070092config 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
Ingo Molnar408894e2006-01-09 15:59:20 -0800102config DEBUG_MUTEXES
103 bool "Mutex debugging, deadlock detection"
Tim Chencca57c52006-04-18 22:21:47 -0700104 default n
Ingo Molnar408894e2006-01-09 15:59:20 -0800105 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110config 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
119config 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
126config 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
133config 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
140config DEBUG_BUGVERBOSE
141 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
Matt Mackallc8538a72005-05-01 08:59:01 -0700142 depends on BUG
Brian Gerst0d078f62005-10-30 14:59:20 -0800143 depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 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
150config 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160config DEBUG_FS
161 bool "Debug Filesystem"
Jens Axboeae36b882006-03-26 14:38:54 +0200162 depends on SYSFS
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 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
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800170config DEBUG_VM
171 bool "Debug VM"
172 depends on DEBUG_KERNEL
173 help
Nick Piggin13e74442006-01-06 00:10:58 -0800174 Enable this to turn on extended checks in the virtual-memory system
175 that may impact performance.
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800176
177 If unsure, say N.
178
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179config FRAME_POINTER
180 bool "Compile the kernel with frame pointers"
Andi Kleenaeb39982005-09-12 18:49:25 +0200181 depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML)
Paolo 'Blaisorblade' Giarrusso37fce852005-05-28 15:51:59 -0700182 default y if DEBUG_INFO && UML
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 help
184 If you say Y here the resulting kernel image will be slightly larger
Jesper Juhl2a38bcc2005-10-30 15:02:51 -0800185 and slower, but it might give very useful debugging information on
186 some architectures or if you use external debuggers.
Andi Kleenaeb39982005-09-12 18:49:25 +0200187 If you don't debug the kernel, you can say N.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
Jan Beulich604bf5a2006-03-24 03:16:19 -0800189config UNWIND_INFO
190 bool "Compile the kernel with frame unwind information"
Jan Beulich4552d5d2006-06-26 13:57:28 +0200191 depends on !IA64 && !PARISC
192 depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
Jan Beulich604bf5a2006-03-24 03:16:19 -0800193 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
Jan Beulich4552d5d2006-06-26 13:57:28 +0200199config STACK_UNWIND
200 bool "Stack unwind support"
201 depends on UNWIND_INFO
Jan Beulich176a2712006-06-26 13:57:41 +0200202 depends on X86
Jan Beulich4552d5d2006-06-26 13:57:28 +0200203 help
204 This enables more precise stack traces, omitting all unrelated
205 occurrences of pointers into kernel code from the dump.
206
Ingo Molnara9df3d02006-01-14 13:21:33 -0800207config FORCED_INLINING
208 bool "Force gcc to inline functions marked 'inline'"
209 depends on DEBUG_KERNEL
210 default y
211 help
212 This option determines if the kernel forces gcc to inline the functions
213 developers have marked 'inline'. Doing so takes away freedom from gcc to
214 do what it thinks is best, which is desirable for the gcc 3.x series of
215 compilers. The gcc 4.x series have a rewritten inlining algorithm and
216 disabling this option will generate a smaller kernel there. Hopefully
217 this algorithm is so good that allowing gcc4 to make the decision can
218 become the default in the future, until then this option is there to
219 test gcc for this.
220
Paul E. McKenneya241ec62005-10-30 15:03:12 -0800221config RCU_TORTURE_TEST
222 tristate "torture tests for RCU"
223 depends on DEBUG_KERNEL
224 default n
225 help
226 This option provides a kernel module that runs torture tests
227 on the RCU infrastructure. The kernel module may be built
228 after the fact on the running kernel to be tested, if desired.
229
230 Say Y here if you want RCU torture tests to start automatically
231 at boot time (you probably don't).
232 Say M if you want the RCU torture tests to build as a module.
233 Say N if you are unsure.