Call fo comments - raising vfs.ufs.dirhash_reclaimage?

[RW]

On Tue, 8 Oct 2013 16:01:25 -0700
Davide Italiano wrote:


> This could be probably changed -- from what | see even under high
> memory pressure this wasn't a problem but all in all I agree with you
> that we shouldn't loop forever but limit the number of pass on the
> list to a somewhat constant number, to prevent pathological cases.

I don't see any need to loop.


> > I don't believe that's true. Under most circustances the existing
> > scheme free more memory. The only case when yours frees more is
> > when 90% of the entries are locked.
> 
> Well, no. Here you can set the threshold to a more aggressive value so
> that you reclaim more memory every time. Note that this was not
> possible in the previous version, so, if you could have a situation
> where all your cache entries were not touched for 15 or even 30
> seconds they would have kept around, and you can destroy up to 10% of
> them everytime lowmem event is called.

Outside of contrived stress tests I think it's very rare for a
significant fraction of the cache to have been accessed in the last
minute - particularly on large caches where this matters most.