Hi, Please try it out on a -10 VM with something RAM limited - say, 128mb w/ GENERIC. See how it behaves.
I've successfully done buildworlds on 10-i386 with 128mb RAM. Let's try not to break that before releng/10 is cut. thanks, -adrian On 7 October 2013 23:34, Peter Holm <pe...@holm.cc> wrote: > On Mon, Oct 07, 2013 at 07:34:24PM +0200, Davide Italiano wrote: > > > What would perhaps be better than a hardcoded reclaim age would be to > use > > > an LRU-type approach and perhaps set a target percent to reclaim. > That is, > > > suppose you were to reclaim the oldest 10% of hashes on each lowmem > call > > > (and make the '10%' the tunable value). Then you will always make > some amount > > > of progress in a low memory situation (and if the situation remains > dire you > > > will eventually empty the entire cache), but the effective maximum age > will > > > be more dynamic. Right now if you haven't touched UFS in 5 seconds it > > > throws the entire thing out on the first lowmem event. The > LRU-approach would > > > only throw the oldest 10% out on the first call, but eventually throw > it all out > > > if the situation remains dire. > > > > > > -- > > > John Baldwin > > > _______________________________________________ > > > freebsd...@freebsd.org mailing list > > > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > > > To unsubscribe, send any mail to "freebsd-fs-unsubscr...@freebsd.org" > > > > I liked your idea more than what's available in HEAD right now and I > > implemented it. > > http://people.freebsd.org/~davide/review/ufs_direclaimage.diff > > I was unsure what kind of heuristic I should choose to select which > > (10% of) entries should be evicted so I just removed the first 10% > > ones from the head of the ufs_dirhash list (which should be the > > oldest). > > The code keeps rescanning the cache until 10% (or, the percentage set > > via SYSCTL) of the entry are freed, but probably we can discuss if > > this limit could be relaxed and just do a single scan over the list. > > Unfortunately I haven't a testcase to prove the effectiveness (or > > non-effectiveness) of the approach but I think either Ivan or Peter > > could be able to give it a spin, maybe. > > > > I gave this patch a spin for 12 hours without finding any problems. > I can do more testing at a later time, if you want to. > > - Peter > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org" > _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
