6b1d174b0c
Extend the ratelimiting facility to print the amount of suppressed lines when it is being released. This use case is aimed at short-termed, burst-like users for which we want to output the suppressed lines stats only once, after it has been disposed of. For an example, see /dev/kmsg usage in a follow-on patch. Also, change the printk() line we issue on release to not use "callbacks" as it is misleading: we're not suppressing callbacks but printk() calls. This has been separated from a previous patch by Linus. Link: http://lkml.kernel.org/r/20160716061745.15795-2-bp@alien8.de Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Dave Young <dyoung@redhat.com> Cc: Franck Bui <fbui@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
110 lines
2.5 KiB
C
110 lines
2.5 KiB
C
#ifndef _LINUX_RATELIMIT_H
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#define _LINUX_RATELIMIT_H
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#include <linux/param.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#define DEFAULT_RATELIMIT_INTERVAL (5 * HZ)
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#define DEFAULT_RATELIMIT_BURST 10
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/* issue num suppressed message on exit */
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#define RATELIMIT_MSG_ON_RELEASE BIT(0)
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struct ratelimit_state {
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raw_spinlock_t lock; /* protect the state */
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int interval;
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int burst;
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int printed;
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int missed;
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unsigned long begin;
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unsigned long flags;
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};
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#define RATELIMIT_STATE_INIT(name, interval_init, burst_init) { \
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.lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
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.interval = interval_init, \
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.burst = burst_init, \
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}
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#define RATELIMIT_STATE_INIT_DISABLED \
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RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)
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#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init) \
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\
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struct ratelimit_state name = \
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RATELIMIT_STATE_INIT(name, interval_init, burst_init) \
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static inline void ratelimit_state_init(struct ratelimit_state *rs,
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int interval, int burst)
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{
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memset(rs, 0, sizeof(*rs));
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raw_spin_lock_init(&rs->lock);
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rs->interval = interval;
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rs->burst = burst;
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}
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static inline void ratelimit_default_init(struct ratelimit_state *rs)
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{
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return ratelimit_state_init(rs, DEFAULT_RATELIMIT_INTERVAL,
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DEFAULT_RATELIMIT_BURST);
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}
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static inline void ratelimit_state_exit(struct ratelimit_state *rs)
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{
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if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE))
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return;
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if (rs->missed) {
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pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
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current->comm, rs->missed);
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rs->missed = 0;
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}
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}
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static inline void
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ratelimit_set_flags(struct ratelimit_state *rs, unsigned long flags)
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{
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rs->flags = flags;
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}
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extern struct ratelimit_state printk_ratelimit_state;
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extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
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#define __ratelimit(state) ___ratelimit(state, __func__)
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#ifdef CONFIG_PRINTK
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#define WARN_ON_RATELIMIT(condition, state) \
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WARN_ON((condition) && __ratelimit(state))
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#define WARN_RATELIMIT(condition, format, ...) \
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({ \
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static DEFINE_RATELIMIT_STATE(_rs, \
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DEFAULT_RATELIMIT_INTERVAL, \
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DEFAULT_RATELIMIT_BURST); \
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int rtn = !!(condition); \
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\
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if (unlikely(rtn && __ratelimit(&_rs))) \
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WARN(rtn, format, ##__VA_ARGS__); \
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\
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rtn; \
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})
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#else
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#define WARN_ON_RATELIMIT(condition, state) \
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WARN_ON(condition)
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#define WARN_RATELIMIT(condition, format, ...) \
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({ \
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int rtn = WARN(condition, format, ##__VA_ARGS__); \
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rtn; \
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})
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#endif
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#endif /* _LINUX_RATELIMIT_H */
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