Messages in this thread | | | Date | Mon, 20 Oct 2014 10:27:50 +0200 | Subject | Re: [uml-devel] [UM] Long loop in __getnsdayoftime() after resume from ram | From | Richard Weinberger <> |
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On Sun, Oct 19, 2014 at 2:39 PM, Thomas Meyer <thomas@m3y3r.de> wrote: > Hello, > > in UML kernel I get a long cpu using loop in __getnstimeofday() > (kernel/time/timekeeping.c:315) in the call of timespec_add_ns(), > when I left the host kernel suspended to ram for a few hours and resume > again. > this is because it seems like the tk->xtime_sec wasn't updated yet, but > the nsecs were. nsecs can be as high as 8111000111000111000l > > the function timespec_add_ns() (include/linux/time.h:266) will call > __iter_div_u64_rem() which has an optimized loop for the case > that the dividend is not much bigger as the divisior. > but this isn't the case for resume from ram on the host kernel. > > any ideas how to fix this? is it possible to intercept the resume from > ram and update the timekeeper->xtime_sec somehow? > or can the um arch somehow overwrite timespec_add_ns() to always use > div_u64_rem() instead?
Hmm, does this always happen? At least on my notebook it did not happen. I've started an UML yesterday suspended it and after more than 12h it worked fine today.
BTW: Do you see the issue also then freezing UML using the freezer cgroup? Would be easier to debug. :)
-- Thanks, //richard
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