linux-kernel - Re: [PATCH] kernel.h: Add printk_ratelimited and pr_<level>

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Date:	Thu, 05 Nov 2009 23:16:13 +0900
From:	Naohiro Ooiwa <nooiwa@...aclelinux.com>
To:	Ingo Molnar <mingo@...e.hu>, Joe Perches <joe@...ches.com>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Hiroshi Shimamoto <h-shimamoto@...jp.nec.com>,
	roland@...hat.com, Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Thomas Gleixner <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>, oleg@...hat.com,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] kernel.h: Add printk_ratelimited and pr_<level>_rl

Ingo Molnar wrote:
> * Joe Perches <joe@...ches.com> wrote:
> 
>> 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.
>>
>> Signed-off-by: Joe Perches <joe@...ches.com>
>>
>> diff --git a/include/linux/kernel.h b/include/linux/kernel.h
>> index f4e3184..555560c 100644
>> --- a/include/linux/kernel.h
>> +++ b/include/linux/kernel.h
>> @@ -407,6 +407,50 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
>>  #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_rl(fmt, ...) \
>> +        printk_ratelimited(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__)
>> +#define pr_alert_rl(fmt, ...) \
>> +        printk_ratelimited(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
>> +#define pr_crit_rl(fmt, ...) \
>> +        printk_ratelimited(KERN_CRIT pr_fmt(fmt), ##__VA_ARGS__)
>> +#define pr_err_rl(fmt, ...) \
>> +        printk_ratelimited(KERN_ERR pr_fmt(fmt), ##__VA_ARGS__)
>> +#define pr_warning_rl(fmt, ...) \
>> +        printk_ratelimited(KERN_WARNING pr_fmt(fmt), ##__VA_ARGS__)
>> +#define pr_notice_rl(fmt, ...) \
>> +        printk_ratelimited(KERN_NOTICE pr_fmt(fmt), ##__VA_ARGS__)
>> +#define pr_info_rl(fmt, ...) \
>> +        printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
>> +/* no pr_cont_rl, don't do that... */
>> +/* If you are writing a driver, please use dev_dbg instead */
>> +#if defined(DEBUG)
>> +#define pr_debug_rl(fmt, ...) \
>> +	printk_ratelimited(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__)
>> +#else
>> +#define pr_debug_rl(fmt, ...) \
>> +	({ if (0) printk_ratelimited(KERN_DEBUG pr_fmt(fmt), \
>> +				     ##__VA_ARGS__); 0; })
>> +#endif
>> +
> 
> Looks like a useful addition. Somewhat bloatier, but then again, more 
> correct and the bloat problem can be solved by explicit state 
> definitions.
> 
> 	Ingo

I waiting for this patch to merge.
And then, I think I will remake my patch.

How do you delete printk_ratelimit() in this patch at a same time ?

I have a personal question.
Why aren't they codes in the include/linux/ratelimit.h ?


Thanks.
Naohiro Ooiwa

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