On 21 January 2015 at 10:15, Gleb Smirnoff <gleb...@freebsd.org> wrote: > Sean, > > On Tue, Jan 20, 2015 at 04:22:44PM -0800, Sean Bruno wrote: > S> In our universe, this commit (right or wrong) resolved our panics. I > S> think that there is some room for improvement based on the commentary > S> in this thread, but some people do indeed prefer stability over > S> performance. I hope we can come to a middle ground somewhere here. > > Sorry, but this sounds very much like alchemy. We poured this stuff > into that stuff and yield in gold precipitate. We don't understand > what's going on, but let's record the recipe into our tome of aclhemy > wisdom. > > So alchemy never came to a scientific level, and chemistry evolved > as science only when researchers started to measure, explain and > understand. > > If we treat our precious kernel in alchemy way, we will follow > the path of alchemy, except that it took centuries for alchemy to > die, and for a software product it would take a few years. > > So, for me Kip ideas sound very sensible. There could be a race > somewhere else. You tweak callout subsystem in any direction, > timings of events in kernel shift, your race is hidden. > > If we fix problems w/o understanding them, we are going alchemy way.
Hi, I don't think it's quite this bad. They originally found that things were spinning for way too long. Hans found something similar and determined/concluded that the migration code in callouts was racy-by-design and dramatically simplified it and also put very hard constraints on what is a valid situation to support migrating from one callwheel to another. Now we have fallout which we can either address or back out until the callout stuff is again reviewed/fixed. I don't think it's as alchemic as is being promoted. -a _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
