On 2014-06-27 05:50, Luigi Rizzo wrote: > On Fri, Jun 27, 2014 at 11:27:56AM +0200, Trond Endrest?l wrote: >> On Fri, 27 Jun 2014 11:14+0200, Luigi Rizzo wrote: >> >>> Hi, >>> I have frequently found myself using sysctls to control some kernel >>> feature where a string would be a better (and sometimes the only) >>> option than using a numeric value, yet the internal representation >>> should be numeric for speed and robustness. >>> Examples are the kern.timecounter, the default scheduler in dummynet, >>> and now in netmap the selection between native and emulated mode. >>> I am sure many of you can come up with other cases. >>> >>> I wonder if we have some support for that already in the sysctl code, >>> or i should build a generic one next time i need to do that. >> >> In C, according to sysctl(3) you could use sysctlnametomib(). >> I might have misinterpreted the problem domain. > > different problem. Example below: > right now i have dev.netmap.admode which can assume integer values, > i do not need a special handler, and the code in the kernel uses > 1, 2 or "everything else" to decide what to do (resetting > "everything else" to 0 opportunistically). > > I want to have a generic handler that accepts a set of predefined > string values (specifically "any native emulated") and converts > them to integers through some user-specificed mapping so the > kernel can still do the quick tests but users don't have > to remember what '2' means > > cheers > luigi > _______________________________________________ > freebsd-current_at_freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe_at_freebsd.org" > If i understand what you are looking for, it sounds like what vfs.zfs.vol.mode uses. the values are 0, 1 or 2, but can also be assigned using the keywords 'geom', 'dev', or 'none' -- Allan Jude
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