| config PRINTK_TIME | |
| bool "Show timing information on printks" | |
| help | |
| Selecting this option causes timing information to be | |
| included in printk output. This allows you to measure | |
| the interval between kernel operations, including bootup | |
| operations. This is useful for identifying long delays | |
| in kernel startup. | |
| config MAGIC_SYSRQ | |
| bool "Magic SysRq key" | |
| depends on !UML | |
| help | |
| If you say Y here, you will have some control over the system even | |
| if the system crashes for example during kernel debugging (e.g., you | |
| will be able to flush the buffer cache to disk, reboot the system | |
| immediately or dump some status information). This is accomplished | |
| by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
| also works on a serial console (on PC hardware at least), if you | |
| send a BREAK and then within 5 seconds a command keypress. The | |
| keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
| unless you really know what this hack does. | |
| config DEBUG_KERNEL | |
| bool "Kernel debugging" | |
| help | |
| Say Y here if you are developing drivers or trying to debug and | |
| identify kernel problems. | |
| config LOG_BUF_SHIFT | |
| int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL | |
| range 12 21 | |
| default 17 if S390 | |
| default 16 if X86_NUMAQ || IA64 | |
| default 15 if SMP | |
| default 14 | |
| help | |
| Select kernel log buffer size as a power of 2. | |
| Defaults and Examples: | |
| 17 => 128 KB for S/390 | |
| 16 => 64 KB for x86 NUMAQ or IA-64 | |
| 15 => 32 KB for SMP | |
| 14 => 16 KB for uniprocessor | |
| 13 => 8 KB | |
| 12 => 4 KB | |
| config DETECT_SOFTLOCKUP | |
| bool "Detect Soft Lockups" | |
| depends on DEBUG_KERNEL | |
| default y | |
| help | |
| Say Y here to enable the kernel to detect "soft lockups", | |
| which are bugs that cause the kernel to loop in kernel | |
| mode for more than 10 seconds, without giving other tasks a | |
| chance to run. | |
| When a soft-lockup is detected, the kernel will print the | |
| current stack trace (which you should report), but the | |
| system will stay locked up. This feature has negligible | |
| overhead. | |
| (Note that "hard lockups" are separate type of bugs that | |
| can be detected via the NMI-watchdog, on platforms that | |
| support it.) | |
| config SCHEDSTATS | |
| bool "Collect scheduler statistics" | |
| depends on DEBUG_KERNEL && PROC_FS | |
| help | |
| If you say Y here, additional code will be inserted into the | |
| scheduler and related routines to collect statistics about | |
| scheduler behavior and provide them in /proc/schedstat. These | |
| stats may be useful for both tuning and debugging the scheduler | |
| If you aren't debugging the scheduler or trying to tune a specific | |
| application, you can say N to avoid the very slight overhead | |
| this adds. | |
| config DEBUG_SLAB | |
| bool "Debug slab memory allocations" | |
| depends on DEBUG_KERNEL && SLAB | |
| help | |
| Say Y here to have the kernel do limited verification on memory | |
| allocation as well as poisoning memory on free to catch use of freed | |
| memory. This can make kmalloc/kfree-intensive workloads much slower. | |
| config DEBUG_SLAB_LEAK | |
| bool "Memory leak debugging" | |
| depends on DEBUG_SLAB | |
| config DEBUG_PREEMPT | |
| bool "Debug preemptible kernel" | |
| depends on DEBUG_KERNEL && PREEMPT | |
| default y | |
| help | |
| If you say Y here then the kernel will use a debug variant of the | |
| commonly used smp_processor_id() function and will print warnings | |
| if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
| will detect preemption count underflows. | |
| config DEBUG_MUTEXES | |
| bool "Mutex debugging, deadlock detection" | |
| default y | |
| depends on DEBUG_KERNEL | |
| help | |
| This allows mutex semantics violations and mutex related deadlocks | |
| (lockups) to be detected and reported automatically. | |
| config DEBUG_SPINLOCK | |
| bool "Spinlock debugging" | |
| depends on DEBUG_KERNEL | |
| help | |
| Say Y here and build SMP to catch missing spinlock initialization | |
| and certain other kinds of spinlock errors commonly made. This is | |
| best used in conjunction with the NMI watchdog so that spinlock | |
| deadlocks are also debuggable. | |
| config DEBUG_SPINLOCK_SLEEP | |
| bool "Sleep-inside-spinlock checking" | |
| depends on DEBUG_KERNEL | |
| help | |
| If you say Y here, various routines which may sleep will become very | |
| noisy if they are called with a spinlock held. | |
| config DEBUG_KOBJECT | |
| bool "kobject debugging" | |
| depends on DEBUG_KERNEL | |
| help | |
| If you say Y here, some extra kobject debugging messages will be sent | |
| to the syslog. | |
| config DEBUG_HIGHMEM | |
| bool "Highmem debugging" | |
| depends on DEBUG_KERNEL && HIGHMEM | |
| help | |
| This options enables addition error checking for high memory systems. | |
| Disable for production systems. | |
| config DEBUG_BUGVERBOSE | |
| bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED | |
| depends on BUG | |
| depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV | |
| default !EMBEDDED | |
| help | |
| Say Y here to make BUG() panics output the file name and line number | |
| of the BUG call as well as the EIP and oops trace. This aids | |
| debugging but costs about 70-100K of memory. | |
| config DEBUG_INFO | |
| bool "Compile the kernel with debug info" | |
| depends on DEBUG_KERNEL | |
| help | |
| If you say Y here the resulting kernel image will include | |
| debugging info resulting in a larger kernel image. | |
| Say Y here only if you plan to debug the kernel. | |
| If unsure, say N. | |
| config DEBUG_IOREMAP | |
| bool "Enable ioremap() debugging" | |
| depends on DEBUG_KERNEL && PARISC | |
| help | |
| Enabling this option will cause the kernel to distinguish between | |
| ioremapped and physical addresses. It will print a backtrace (at | |
| most one every 10 seconds), hopefully allowing you to see which | |
| drivers need work. Fixing all these problems is a prerequisite | |
| for turning on USE_HPPA_IOREMAP. The warnings are harmless; | |
| the kernel has enough information to fix the broken drivers | |
| automatically, but we'd like to make it more efficient by not | |
| having to do that. | |
| config DEBUG_FS | |
| bool "Debug Filesystem" | |
| depends on DEBUG_KERNEL && SYSFS | |
| help | |
| debugfs is a virtual file system that kernel developers use to put | |
| debugging files into. Enable this option to be able to read and | |
| write to these files. | |
| If unsure, say N. | |
| config DEBUG_VM | |
| bool "Debug VM" | |
| depends on DEBUG_KERNEL | |
| help | |
| Enable this to turn on extended checks in the virtual-memory system | |
| that may impact performance. | |
| If unsure, say N. | |
| config FRAME_POINTER | |
| bool "Compile the kernel with frame pointers" | |
| depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML) | |
| default y if DEBUG_INFO && UML | |
| help | |
| If you say Y here the resulting kernel image will be slightly larger | |
| and slower, but it might give very useful debugging information on | |
| some architectures or if you use external debuggers. | |
| If you don't debug the kernel, you can say N. | |
| config UNWIND_INFO | |
| bool "Compile the kernel with frame unwind information" | |
| depends on !IA64 | |
| depends on !MODULES || !(MIPS || PARISC || PPC || SUPERH || SPARC64 || V850) | |
| help | |
| If you say Y here the resulting kernel image will be slightly larger | |
| but not slower, and it will give very useful debugging information. | |
| If you don't debug the kernel, you can say N, but we may not be able | |
| to solve problems without frame unwind information or frame pointers. | |
| config FORCED_INLINING | |
| bool "Force gcc to inline functions marked 'inline'" | |
| depends on DEBUG_KERNEL | |
| default y | |
| help | |
| This option determines if the kernel forces gcc to inline the functions | |
| developers have marked 'inline'. Doing so takes away freedom from gcc to | |
| do what it thinks is best, which is desirable for the gcc 3.x series of | |
| compilers. The gcc 4.x series have a rewritten inlining algorithm and | |
| disabling this option will generate a smaller kernel there. Hopefully | |
| this algorithm is so good that allowing gcc4 to make the decision can | |
| become the default in the future, until then this option is there to | |
| test gcc for this. | |
| config RCU_TORTURE_TEST | |
| tristate "torture tests for RCU" | |
| depends on DEBUG_KERNEL | |
| default n | |
| help | |
| This option provides a kernel module that runs torture tests | |
| on the RCU infrastructure. The kernel module may be built | |
| after the fact on the running kernel to be tested, if desired. | |
| Say Y here if you want RCU torture tests to start automatically | |
| at boot time (you probably don't). | |
| Say M if you want the RCU torture tests to build as a module. | |
| Say N if you are unsure. |