[PATCH 1/3] Add ratelimited printk for different alert levels

[Joe Perches]

On Wed, 2012-09-12 at 03:43 +0530, raghu.prabhu13 at gmail.com wrote:
> Ratelimited printk will be useful in printing xfs messages which are otherwise
> not required to be printed always due to their high rate (to prevent kernel ring
> buffer from overflowing), while at the same time required to be printed.
[]
> diff --git a/fs/xfs/xfs_message.h b/fs/xfs/xfs_message.h
[]
> @@ -30,6 +32,32 @@ void xfs_debug(const struct xfs_mount *mp, const char *fmt, ...)
>  }
>  #endif
>  
> +#define xfs_printk_ratelimited(xfs_printk, dev, fmt, ...)		\
> +do {									\
> +	static DEFINE_RATELIMIT_STATE(_rs,				\
> +				      DEFAULT_RATELIMIT_INTERVAL,	\
> +				      DEFAULT_RATELIMIT_BURST);		\
> +	if (__ratelimit(&_rs))						\
> +		xfs_printk(dev, fmt, ##__VA_ARGS__);			\
> +} while (0)

It might be better to use an xfs singleton RATELIMIT_STATE

DEFINE_RATELIMIT_STATE(xfs_rs);
...
#define xfs_printk_ratelimited(xfs_printk, dev, fmt, ...)		\
do {									\
	if (__ratelimit(&xfs_rs))					\
		xfs_printk(dev, fmt, ##__VA_ARGS__);			\
} while (0)