Tony Luck found that using the "uptime" trace clock that uses jiffies
as a counter was converted to nanoseconds (silly), and after 1 hour 11 minutes and 34 seconds, this monotonic clock would wrap, causing havoc with the tracing system and making the clock useless. He converted that clock to use jiffies_64 and made it into a counter instead of nanosecond conversions, and displayed the clock with the straight jiffy count, which works much better than it did in the past. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAABAgAGBQJTzcD+AAoJEKQekfcNnQGuy4UH/2IaAlJov97GTlYcpA6CCOfQ S6KYN93V/wbJpoRhcVIyk21ugolPCPCA+W8QEHU/yIzTDuy4VzkiYDfEZSNWL9bF 36dmYyNQdeFkfhVK0sHW7/OvF/YcbMsd70N1+NuwFu0m/sDFKlPWiGe8F0GDyRQb mKDBiAVAAhDtMWycff3iUgA7eJffejf6Hs6Ve9UdxQ4FxvDaS9ISCRzzWkEktlnw RPHvZZRCd+TvtugjGdfusHXhnKSdZSkt5c0R0DyyTebW1Wgrq9dJGXxuth+hdoww 9iQ6o2YhhoxIo49BwxkTJMsLsS4jC+2KmMEepQ3H7BjTUYg5tWMd9kWAAtxKuDI= =3sF+ -----END PGP SIGNATURE----- Merge tag 'trace-fixes-v3.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull trace fix from Steven Rostedt: "Tony Luck found that using the "uptime" trace clock that uses jiffies as a counter was converted to nanoseconds (silly), and after 1 hour 11 minutes and 34 seconds, this monotonic clock would wrap, causing havoc with the tracing system and making the clock useless. He converted that clock to use jiffies_64 and made it into a counter instead of nanosecond conversions, and displayed the clock with the straight jiffy count, which works much better than it did in the past" * tag 'trace-fixes-v3.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Fix wraparound problems in "uptime" trace clock
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Коммит
8dcc3be2a4
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@ -823,7 +823,7 @@ static struct {
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{ trace_clock_local, "local", 1 },
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{ trace_clock_global, "global", 1 },
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{ trace_clock_counter, "counter", 0 },
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{ trace_clock_jiffies, "uptime", 1 },
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{ trace_clock_jiffies, "uptime", 0 },
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{ trace_clock, "perf", 1 },
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ARCH_TRACE_CLOCKS
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};
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@ -59,13 +59,14 @@ u64 notrace trace_clock(void)
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/*
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* trace_jiffy_clock(): Simply use jiffies as a clock counter.
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* Note that this use of jiffies_64 is not completely safe on
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* 32-bit systems. But the window is tiny, and the effect if
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* we are affected is that we will have an obviously bogus
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* timestamp on a trace event - i.e. not life threatening.
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*/
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u64 notrace trace_clock_jiffies(void)
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{
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u64 jiffy = jiffies - INITIAL_JIFFIES;
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/* Return nsecs */
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return (u64)jiffies_to_usecs(jiffy) * 1000ULL;
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return jiffies_64_to_clock_t(jiffies_64 - INITIAL_JIFFIES);
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}
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/*
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