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bintime()/binuptime(). The algorithm to read the consistent snapshot of current timehand is repeated in each accessor, including the details proper rollup detection and synchronization with the writer. In fact there are only two different kind of readers: one for bintime()/binuptime() which has to do the in-place calculation, and another kind which fetches some member from struct timehand. Extract the logic into type-checked macros, GETTHBINTIME() for bintime calculation, and GETTHMEMBER() for safe read of a structure' member. This way, the synchronization is only written in bintime_off() and getthmember(). In bintime_off(), use overflow-safe calculation of th_scale * delta(timecounter). In tc_windup, pre-calculate the min delta value which overflows and require slow algorithm, into the new timehands th_large_delta member. This part with overflow fix was written by Bruce Evans. Reported by: Mark Millard <marklmi@yahoo.com> (the overflow issue) Tested by: pho Discussed with: emaste Sponsored by: The FreeBSD Foundation (kib) MFC after: 3 weeks
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