[OpenAFS] Re: Tuning the -daemons.

Andrew Deason adeason@sinenomine.net
Tue, 19 Apr 2011 10:21:10 -0500

On Tue, 19 Apr 2011 14:54:38 +0200 (CEST)
Harald Barth <haba@kth.se> wrote:

> > We believe that this behaviour is fixed in 1.6.0pre4.
> Do you have any idea when it was introduced?

The underlying issue I think has always existed: xvcache must be
write-locked for vcache traversal, and we traverse vcaches looking for
something to flush, and a flush may hit a fileserver for a
GiveUpCallBacks call when we flush VCBs when we run out of CBRs. I think
all of that has always been the case, from looking at git history.
("Always" meaning back to OpenAFS 1.0.)

Maybe dynamic vcaches made this more likely to be hit, though (which
would be 1.4.10, Linux-only). Before/without those, I think you have to
run out of free vcache entries before you hit the relevant code path,
which I expect happens less often than we ShakeLooseVCaches these days.

Andrew Deason