From 3fff4c42bd0a89869a0eb1e7874cc06ffa4aa0f5 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 22 Sep 2009 16:18:09 +0200 Subject: printk: Remove ratelimit.h from kernel.h Decouple kernel.h from ratelimit.h: the global declaration of printk's ratelimit_state is not needed, and it leads to messy circular dependencies due to ratelimit.h's (new) adding of a spinlock_types.h include. Cc: Peter Zijlstra Cc: Andrew Morton Cc: Linus Torvalds Cc: David S. Miller LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2b5b1e0899a8..3305f33201be 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -15,7 +15,6 @@ #include #include #include -#include #include #include #include @@ -241,7 +240,6 @@ asmlinkage int vprintk(const char *fmt, va_list args) asmlinkage int printk(const char * fmt, ...) __attribute__ ((format (printf, 1, 2))) __cold; -extern struct ratelimit_state printk_ratelimit_state; extern int printk_ratelimit(void); extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msec); -- cgit v1.2.3 From 5c828713358cb9df8aa174371edcbbb62203a490 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Fri, 23 Oct 2009 14:58:11 +0200 Subject: ratelimit: Make suppressed output messages more useful Today I got: [39648.224782] Registered led device: iwl-phy0::TX [40676.545099] __ratelimit: 246 callbacks suppressed [40676.545103] abcdef[23675]: segfault at 0 ... as you can see the ratelimit message contains a function prefix. Since this is always __ratelimit, this wont help much. This patch changes __ratelimit and printk_ratelimit to print the function name that calls ratelimit. This will pinpoint the responsible function, as long as not several different places call ratelimit with the same ratelimit state at the same time. In that case we catch only one random function that calls ratelimit after the wait period. Signed-off-by: Christian Borntraeger Cc: Dave Young Cc: Linus Torvalds CC: Andrew Morton LKML-Reference: <200910231458.11832.borntraeger@de.ibm.com> Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3305f33201be..21d0d822c716 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -240,7 +240,8 @@ asmlinkage int vprintk(const char *fmt, va_list args) asmlinkage int printk(const char * fmt, ...) __attribute__ ((format (printf, 1, 2))) __cold; -extern int printk_ratelimit(void); +extern int __printk_ratelimit(const char *func); +#define printk_ratelimit() __printk_ratelimit(__func__) extern bool printk_timed_ratelimit(unsigned long *caller_jiffies, unsigned int interval_msec); -- cgit v1.2.3 From 03889384cee7a198a79447c1ea6aca2c8e54d155 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 11 Dec 2009 09:48:22 -0500 Subject: tracing: Add trace_dump_stack() I've been asked a few times about how to find out what is calling some location in the kernel. One way is to use dynamic function tracing and implement the func_stack_trace. But this only finds out who is calling a particular function. It does not tell you who is calling that function and entering a specific if conditional. I have myself implemented a quick version of trace_dump_stack() for this purpose a few times, and just needed it now. This is when I realized that this would be a good tool to have in the kernel like trace_printk(). Using trace_dump_stack() is similar to dump_stack() except that it writes to the trace buffer instead and can be used in critical locations. For example: @@ -5485,8 +5485,12 @@ need_resched_nonpreemptible: if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { if (unlikely(signal_pending_state(prev->state, prev))) prev->state = TASK_RUNNING; - else + else { deactivate_task(rq, prev, 1); + trace_printk("Deactivating task %s:%d\n", + prev->comm, prev->pid); + trace_dump_stack(); + } switch_count = &prev->nvcsw; } Produces: <...>-3249 [001] 296.105269: schedule: Deactivating task ntpd:3249 <...>-3249 [001] 296.105270: => schedule => schedule_hrtimeout_range => poll_schedule_timeout => do_select => core_sys_select => sys_select => system_call_fastpath Signed-off-by: Steven Rostedt --- include/linux/kernel.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3fa4c590cf12..5ad4199fb073 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -492,6 +492,8 @@ extern int __trace_printk(unsigned long ip, const char *fmt, ...) __attribute__ ((format (printf, 2, 3))); +extern void trace_dump_stack(void); + /* * The double __builtin_constant_p is because gcc will give us an error * if we try to allocate the static variable to fmt if it is not a -- cgit v1.2.3 From e36c54582c6f14adc9e10473e2aec2cc4f0acc03 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 14 Dec 2009 15:58:33 -0500 Subject: tracing: Fix return of trace_dump_stack() The trace_dump_stack() returned a value for a void function. Also, added the missing stub for trace_dump_stack() when tracing is not configured. Reported-by: Ingo Molnar LKML-Reference: <20091214162713.GA31060@elte.hu> Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- include/linux/kernel.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 5ad4199fb073..f1dc752da0d2 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -527,6 +527,7 @@ trace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2))); static inline void tracing_start(void) { } static inline void tracing_stop(void) { } static inline void ftrace_off_permanent(void) { } +static inline void trace_dump_stack(void) { } static inline int trace_printk(const char *fmt, ...) { -- cgit v1.2.3 From 00b55864bb37200d7f05143c44f5e2edfc8c4578 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 14 Dec 2009 18:00:14 -0800 Subject: dynamic_debug.h/kernel.h: Remove KBUILD_MODNAME from dynamic_pr_debug If CONFIG_DYNAMIC_DEBUG is enabled and a source file has: #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include dynamic_debug.h will duplicate KBUILD_MODNAME in the output string. Remove the use of KBUILD_MODNAME from the output format string generated by dynamic_debug.h If CONFIG_DYNAMIC_DEBUG is not enabled, no compile-time check is done to printk/dev_printk arguments. Add it. Signed-off-by: Joe Perches Cc: Jason Baron Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 3fa4c590cf12..a93cdd031aee 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -397,9 +397,8 @@ static inline char *pack_hex_byte(char *buf, u8 byte) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) #elif defined(CONFIG_DYNAMIC_DEBUG) /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */ -#define pr_debug(fmt, ...) do { \ - dynamic_pr_debug(fmt, ##__VA_ARGS__); \ - } while (0) +#define pr_debug(fmt, ...) \ + dynamic_pr_debug(fmt, ##__VA_ARGS__) #else #define pr_debug(fmt, ...) \ ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; }) -- cgit v1.2.3 From 0b2749aa6ca40ff3fe12ebb3fdf010ebad2e9085 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 14 Dec 2009 18:00:19 -0800 Subject: kernel.h: remove initialization of bool in printk_once Don't initialize __print_once. Invert the test to reduce initialized data. defconfig before: $size vmlinux text data bss dec hex filename 6976022 679572 1359668 9015262 898fde vmlinux defconfig after: $size vmlinux text data bss dec hex filename 6976006 679508 1359700 9015214 898fae vmlinux Signed-off-by: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index a93cdd031aee..910db75b1a72 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -251,10 +251,10 @@ extern int printk_delay_msec; * Print a one-time message (analogous to WARN_ONCE() et al): */ #define printk_once(x...) ({ \ - static bool __print_once = true; \ + static bool __print_once; \ \ - if (__print_once) { \ - __print_once = false; \ + if (!__print_once) { \ + __print_once = true; \ printk(x); \ } \ }) -- cgit v1.2.3 From 8a64f336bc1d4aa203b138d29d5a9c414a9fbb47 Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 14 Dec 2009 18:00:25 -0800 Subject: kernel.h: add printk_ratelimited and pr__rl Add a printk_ratelimited statement expression macro that uses a per-call ratelimit_state so that multiple subsystems output messages are not suppressed by a global __ratelimit state. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: s/_rl/_ratelimited/g] Signed-off-by: Joe Perches Cc: Naohiro Ooiwa Cc: Ingo Molnar Cc: Hiroshi Shimamoto Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kernel.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) (limited to 'include/linux/kernel.h') diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 910db75b1a72..4d9c916d06d9 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -404,6 +404,50 @@ static inline char *pack_hex_byte(char *buf, u8 byte) ({ if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); 0; }) #endif +/* + * ratelimited messages with local ratelimit_state, + * no local ratelimit_state used in the !PRINTK case + */ +#ifdef CONFIG_PRINTK +#define printk_ratelimited(fmt, ...) ({ \ + static struct ratelimit_state _rs = { \ + .interval = DEFAULT_RATELIMIT_INTERVAL, \ + .burst = DEFAULT_RATELIMIT_BURST, \ + }; \ + \ + if (!__ratelimit(&_rs)) \ + printk(fmt, ##__VA_ARGS__); \ +}) +#else +/* No effect, but we still get type checking even in the !PRINTK case: */ +#define printk_ratelimited printk +#endif + +#define pr_emerg_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__) +#define pr_alert_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__) +#define pr_crit_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__) +#define pr_err_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__) +#define pr_warning_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__) +#define pr_notice_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__) +#define pr_info_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__) +/* no pr_cont_ratelimited, don't do that... */ +/* If you are writing a driver, please use dev_dbg instead */ +#if defined(DEBUG) +#define pr_debug_ratelimited(fmt, ...) \ + printk_ratelimited(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) +#else +#define pr_debug_ratelimited(fmt, ...) \ + ({ if (0) printk_ratelimited(KERN_DEBUG pr_fmt(fmt), \ + ##__VA_ARGS__); 0; }) +#endif + /* * General tracing related utility functions - trace_printk(), * tracing_on/tracing_off and tracing_start()/tracing_stop -- cgit v1.2.3