Messages in this thread |  | | Date | Fri, 5 Oct 2001 06:41:39 -0700 | From | Jonathan Lundell <> | Subject | Re: Finegrained a/c/mtime was Re: Directory notification pr |
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At 3:27 PM -0700 2001-10-05, Petr Vandrovec wrote: >On 5 Oct 01 at 14:15, Padraig Brady wrote: >> >Another advantage of using the real time instead of a counter is that >> >you can easily merge the both values into a single 64bit value and do >> >arithmetic on it in user space. With a generation counter you would need >> >to work with number pairs, which is much more complex. >> > >> ?? >> if (file->mtime != mtime || file->gen_count != gen_count) >> file_changed=1; > >make needs comparing timestamps between two files. I cannot imagine >how you can get this working (without network filesystem you can >have global gen_count, but with network filesystem each server has >its own gen_count... and using world-wide nanoseconds instead of world-wide >gen_count looks much simpler to me ;-) )
Except for the world-wide-nanosecond-resolution synchronization problem....
Even keeping cycle-counter-based systems in sync within SMP systems seems problematical, depending on how the counters are implemented. -- /Jonathan Lundell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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