[OpenAFS-devel] Re: freezes acessing /afs/.git

[chas williams - CONTRACTOR]

On Thu, 14 Aug 2014 14:46:51 -0500
Andrew Deason <adeason@sinenomine.net> wrote:

> But we already cache the positive results; you just said in the next
> sentence that we do. The subsystem that remembers cell information has
> logic for timeouts and has the structure for remembering the cells; you
> just duplicated it it an entirely separate place except only for
> negative results for some reason. So now we'd have two separate caches
> to deal with, which seems rather confusing and error prone, and I see no
> reason to do it like that.

For the reasons I stated earlier -- the negative name space is much
larger than the positive name space.  I don't see a pressing reason to
modify the kernel's cache of cell name to address mappings to add
hashing support to efficiently deal with a large negative name space.

The kernel is caching cell information.  The new code is caching DNS
information (because sadly your local resolver doesn't do a very good
job).  We could cache positive DNS results and it wouldn't be hard to
do but since that currently isn't an issue, I choose not to do it.