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authorJon Hunter <jon-hunter@ti.com>2009-08-18 12:45:10 -0500
committerThomas Gleixner <tglx@linutronix.de>2009-11-13 20:46:24 +0100
commit98962465ed9e6ea99c38e0af63fe1dcb5a79dc25 (patch)
treef3f69ad8f6cd47e72a75da6de49eb3402f15cd9b /include/linux/time.h
parent529eaccd900a59724619b4a6ef6579fd518d5218 (diff)
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nohz: Prevent clocksource wrapping during idle
The dynamic tick allows the kernel to sleep for periods longer than a single tick, but it does not limit the sleep time currently. In the worst case the kernel could sleep longer than the wrap around time of the time keeping clock source which would result in losing track of time. Prevent this by limiting it to the safe maximum sleep time of the current time keeping clock source. The value is calculated when the clock source is registered. [ tglx: simplified the code a bit and massaged the commit msg ] Signed-off-by: Jon Hunter <jon-hunter@ti.com> Cc: John Stultz <johnstul@us.ibm.com> LKML-Reference: <1250617512-23567-2-git-send-email-jon-hunter@ti.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/time.h')
-rw-r--r--include/linux/time.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/time.h b/include/linux/time.h
index fe04e5e..6e026e4 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -148,6 +148,7 @@ extern void monotonic_to_bootbased(struct timespec *ts);
extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
extern int timekeeping_valid_for_hres(void);
+extern u64 timekeeping_max_deferment(void);
extern void update_wall_time(void);
extern void update_xtime_cache(u64 nsec);
extern void timekeeping_leap_insert(int leapsecond);
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