Re: [PATCH 05/50] Dynamic debug: Add more flags

From: Jason Baron
Date: Thu Mar 17 2011 - 13:58:07 EST


On Wed, Mar 16, 2011 at 02:10:43PM -0700, Greg Kroah-Hartman wrote:
> Add flags that allow the user to specify via debugfs whether or not the
> module name, function name, line number and/or thread ID have to be
> included in the printed message.
>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> Cc: Greg Banks <gnb@xxxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
> ---
> Documentation/dynamic-debug-howto.txt | 12 +++++-
> include/linux/dynamic_debug.h | 8 ++++-
> lib/dynamic_debug.c | 60 ++++++++++++++++++++++++++++-----
> 3 files changed, 68 insertions(+), 12 deletions(-)
>
> diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt
> index 58ea64a..e6c4b75 100644
> --- a/Documentation/dynamic-debug-howto.txt
> +++ b/Documentation/dynamic-debug-howto.txt
> @@ -205,12 +205,20 @@ of the characters:
>
> The flags are:
>
> +f
> + Include the function name in the printed message
> +l
> + Include line number in the printed message
> +m
> + Include module name in the printed message
> p
> Causes a printk() message to be emitted to dmesg
> +t
> + Include thread ID in messages not generated from interrupt context
>
> -Note the regexp ^[-+=][scp]+$ matches a flags specification.
> +Note the regexp ^[-+=][flmpt]+$ matches a flags specification.
> Note also that there is no convenient syntax to remove all
> -the flags at once, you need to use "-psc".
> +the flags at once, you need to use "-flmpt".
>
>
> Debug messages during boot process
> diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
> index 1c70028..0c9653f 100644
> --- a/include/linux/dynamic_debug.h
> +++ b/include/linux/dynamic_debug.h
> @@ -31,6 +31,10 @@ struct _ddebug {
> * writes commands to <debugfs>/dynamic_debug/control
> */
> #define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
> +#define _DPRINTK_FLAGS_INCL_MODNAME (1<<1)
> +#define _DPRINTK_FLAGS_INCL_FUNCNAME (1<<2)
> +#define _DPRINTK_FLAGS_INCL_LINENO (1<<3)
> +#define _DPRINTK_FLAGS_INCL_TID (1<<4)
> #define _DPRINTK_FLAGS_DEFAULT 0
> unsigned int flags:8;
> char enabled;
> @@ -42,6 +46,8 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
>
> #if defined(CONFIG_DYNAMIC_DEBUG)
> extern int ddebug_remove_module(const char *mod_name);
> +extern int __dynamic_pr_debug(struct _ddebug *descriptor, const char *fmt, ...)
> + __attribute__ ((format (printf, 2, 3)));
>
> #define dynamic_pr_debug(fmt, ...) do { \
> static struct _ddebug descriptor \
> @@ -50,7 +56,7 @@ extern int ddebug_remove_module(const char *mod_name);
> { KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
> _DPRINTK_FLAGS_DEFAULT }; \
> if (unlikely(descriptor.enabled)) \
> - printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); \
> + __dynamic_pr_debug(&descriptor, pr_fmt(fmt), ##__VA_ARGS__); \
> } while (0)
>

This piece is going to conflict with the jump label update patches, I'm
trying to get into .39. The 'if (unlikely(descriptor.enabled))' bit is
now: 'if (DDEBUG_BRANCH(descriptor.enabled))'. So its a small conflict,
but they wouldn't merge together. So we need to adjust either one (and
make sure they're applied in the correct orer), or drop one.

thanks,

-Jason


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