Messages in this thread | | | Date | Mon, 28 Jan 2013 22:51:22 +0100 | Subject | Re: [PATCH 8/8] cputime: Safely read cputime of full dynticks CPUs | From | Sedat Dilek <> |
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On Mon, Jan 28, 2013 at 8:04 PM, Frederic Weisbecker <fweisbec@gmail.com> wrote: > While remotely reading the cputime of a task running in a > full dynticks CPU, the values stored in utime/stime fields > of struct task_struct may be stale. Its values may be those > of the last kernel <-> user transition time snapshot and > we need to add the tickless time spent since this snapshot. > > To fix this, flush the cputime of the dynticks CPUs on > kernel <-> user transition and record the time / context > where we did this. Then on top of this snapshot and the current > time, perform the fixup on the reader side from task_times() > accessors. > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Li Zhong <zhong@linux.vnet.ibm.com> > Cc: Namhyung Kim <namhyung.kim@lge.com> > Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > Cc: Paul Gortmaker <paul.gortmaker@windriver.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > [fixed kvm module related build errors] > Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com> >
Can you explain a bit what is the difference between "3.8-rc4-nohz3" and "full-dynticks-cputime-for-mingo" patchsets?
Does the latter need no more EXPORT_SYMBOL_GPL for vtime_guest_enter() and vtime_guest_exit() when CONFIG_KVM=m (see [1])?
- Sedat -
[1] https://lkml.org/lkml/2013/1/23/473
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