kernel_samsung_sm7125

jenna

History

John Stultz 830ec0458c time: Fix accumulation bug triggered by long delay. The logarithmic accumulation done in the timekeeping has some overflow protection that limits the max shift value. That means it will take more then shift loops to accumulate all of the cycles. This causes the shift decrement to underflow, which causes the loop to never exit. The simplest fix would be simply to do a: if (shift) shift--; However that is not optimal, as we know the cycle offset is larger then the interval << shift, the above would make shift drop to zero, then we would be spinning for quite awhile accumulating at interval chunks at a time. Instead, this patch only decreases shift if the offset is smaller then cycle_interval << shift. This makes sure we accumulate using the largest chunks possible without overflowing tick_length, and limits the number of iterations through the loop. This issue was found and reported by Sonic Zhang, who also tested the fix. Many thanks your explanation and testing! Reported-by: Sonic Zhang <sonic.adi@gmail.com> Signed-off-by: John Stultz <johnstul@us.ibm.com> Tested-by: Sonic Zhang <sonic.adi@gmail.com> LKML-Reference: <1268948850-5225-1-git-send-email-johnstul@us.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		15 years ago
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Kconfig	Kconfig: eliminate "def_bool n" constructs	16 years ago
Makefile	…
clockevents.c	clockevent: Don't remove broadcast device when cpu is dead	15 years ago
clocksource.c	…
jiffies.c	…
ntp.c	…
tick-broadcast.c	…
tick-common.c	clockevents: Convert to raw_spinlock	15 years ago
tick-internal.h	…
tick-oneshot.c	clockevents: Sanitize min_delta_ns adjustment and prevent overflows	15 years ago
tick-sched.c	…
timecompare.c	timecompare: fix half-Y2K38 problem in timecompare_update while calculating offset	15 years ago
timeconv.c	time: add function to convert between calendar time and broken-down time for universal use	15 years ago
timekeeping.c	time: Fix accumulation bug triggered by long delay.	15 years ago
timer_list.c	clockevents: Sanitize min_delta_ns adjustment and prevent overflows	15 years ago
timer_stats.c	hrtimers: Convert to raw_spinlocks	15 years ago