Messages in this thread | | | Subject | Re: [RFC] Fast assurate clock readable from user space and NMI handler | From | john stultz <> | Date | Tue, 27 Feb 2007 11:40:24 -0800 |
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On Tue, 2007-02-27 at 14:04 -0500, Mathieu Desnoyers wrote: > __get_nsec_offset : reads clock->cycle_last. Should be called with > xtime_lock held. (ok so far, but see below) > > change_clocksource > clock->cycle_last = now; (non atomic 64 bits update. Not protected by > any lock ?) -> this would race with __get_nsec_offset ?
Minor nit (it could probably use a comment fixup): its only called from update_wall_time, which holds xtime_lock.
> update_wall_time > Called from timer interrupt. Holds xtime_lock and has a priority higher > than other interrupts. Other clock->cycle_last protected by > write_seqlock_irqsave.
-john
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