Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH v3]PM/Sleep: Timer quiesce in freeze state | Date | Mon, 26 Jan 2015 16:04:05 +0100 |
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On Monday, January 26, 2015 03:34:22 PM Thomas Gleixner wrote: > On Mon, 26 Jan 2015, Rafael J. Wysocki wrote: > > On Monday, January 26, 2015 03:24:27 PM Thomas Gleixner wrote: > > > On Mon, 26 Jan 2015, Rafael J. Wysocki wrote: > > > > On Monday, January 26, 2015 10:40:24 AM Thomas Gleixner wrote: > > > > > The only remaining issue might be a NMI calling into > > > > > ktime_get_mono_fast_ns() before timekeeping is resumed. Its probably a > > > > > non issue on x86/tsc, but it might be a problem on other platforms > > > > > which turn off devices, clocks, It's not rocket science to prevent > > > > > that. > > > > > > > > I don't see any users of ktime_get_mono_fast_ns() at all, unless some non-trivial > > > > macros are involved. At least grepping for it only returns the definition, > > > > declarations and the line in trace.c. > > > > > > You can trace in NMI and perf is going to use ktime_get_mono_fast_ns() > > > eventually as well. > > > > So I'm not sure how to intercept that to be honest. Any hints? > > If we suspend timekeeping we can make the fast timekeeper point at a > dummy readout function which returns the time at suspend, if the clock > source does not resume automagically. > > As I said TSC should be a non issue, but other stuff might be. We > could make it conditional on CLOCK_SOURCE_SUSPEND_NONSTOP perhaps.
OK, thanks!
Rafael
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