Re: [23/27] kernel.h: add printk_ratelimited and pr__rl

Ben Hutchings
2012-01-24T16:36:12Z

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On Tue, 2012-01-24 at 16:46 +0200, Phil Carmody wrote:
> On 23/01/12 15:41 -0800, ext Greg KH wrote:
> > 2.6.32-longterm review patch. If anyone has any objections, please let me know.
>
> This looks like an added feature with no users in .32 - does it really
> belong in a stable tree?
> (But to be explicit, I have no issue with its contents at all.)

It's required for commit 0bfc96cb77224736dfa35c3c555d37b3646ef35e
('block: fail SCSI passthrough ioctls on partition devices'), though
that hasn't actually been included in this series. I think that's
because there is still ongoing discussion of which error codes need to
be used.

Ben.

> Phil
>
> > ------------------
> >
> >
> > From: Joe Perches <joe@perches.com>
> >
> > commit 8a64f336bc1d4aa203b138d29d5a9c414a9fbb47 upstream.
> >
> > 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 <joe@perches.com>
> > Cc: Naohiro Ooiwa <nooiwa@miraclelinux.com>
> > Cc: Ingo Molnar <mingo@elte.hu>
> > Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
> >
> > ---
> > include/linux/kernel.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 44 insertions(+)
> >
> > --- a/include/linux/kernel.h
> > +++ b/include/linux/kernel.h
> > @@ -407,6 +407,50 @@ static inline char *pack_hex_byte(char *
> > #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
> > *
> >
> >
> > --
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--
Ben Hutchings
Horngren's Observation:
Among economists, the real world is often a special case.

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