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Commit f46c4833 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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[PATCH] Add printk_timed_ratelimit() 



printk_ratelimit() has global state which makes it not useful for callers
which wish to perform ratelimiting at a particular frequency.

Add a printk_timed_ratelimit() which utilises caller-provided state storage to
permit more flexibility.

This function can in fact be used for things other than printk ratelimiting
and is perhaps poorly named.

Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7f6b8876

include/linux/kernel.h

+2 −0
Original line number Diff line number Diff line
@@ -171,6 +171,8 @@ __attribute_const__ roundup_pow_of_two(unsigned long x) 


extern int printk_ratelimit(void);

extern int __printk_ratelimit(int ratelimit_jiffies, int ratelimit_burst);

extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,

				unsigned int interval_msec);



static inline void console_silent(void)

{

kernel/printk.c

+21 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/security.h>

#include <linux/bootmem.h>

#include <linux/syscalls.h>

#include <linux/jiffies.h>



#include <asm/uaccess.h>
@@ -1101,3 +1102,23 @@ int printk_ratelimit(void) 
				printk_ratelimit_burst);

}

EXPORT_SYMBOL(printk_ratelimit);



/**

 * printk_timed_ratelimit - caller-controlled printk ratelimiting

 * @caller_jiffies: pointer to caller's state

 * @interval_msecs: minimum interval between prints

 *

 * printk_timed_ratelimit() returns true if more than @interval_msecs

 * milliseconds have elapsed since the last time printk_timed_ratelimit()

 * returned true.

 */

bool printk_timed_ratelimit(unsigned long *caller_jiffies,

			unsigned int interval_msecs)

{

	if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) {

		*caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs);

		return true;

	}

	return false;

}

EXPORT_SYMBOL(printk_timed_ratelimit);