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

[Andrew Deason]

[sorry about this conversation ping-ponging between -info and -devel,
but I would like to try to keep from having too much devel-y stuff on a
user list...]

On Thu, 14 Aug 2014 08:45:16 -0400
chas williams - CONTRACTOR <chas@cmf.nrl.navy.mil> wrote:

> On Wed, 13 Aug 2014 22:26:36 -0500
> Andrew Deason <adeason@sinenomine.net> wrote:
>
> > can be very slow if we just cache results in the kernel (keep a
> > 'negative' cell struct around).
> 
> Keeping the negative cache in the kernel possibly isn't a good idea.
> At a minimum you would need to bound the size.  I don't think the
> call up to afsd is that slow but if it is it could be fixed.

You need to bound the size anyway. Whether it's kept in afsd or the
kernel I don't want it taking up all the memory in my machine. Caching
it in the kernel means we really don't need to worry about the afsd
upcall speed at all, since that path almost never happens.

But yeah, the speed penalty of the afsd upcall may not be bad; I just
thought the 'struct cell' was an intuitive place for it to go. We don't
need a whole separate structure and framework for the negative cache
entries specifically.

-- 
Andrew Deason
adeason@sinenomine.net