Re: [PATCH 3/6] nfsd: add session slot count to /proc/fs/nfsd/clients/*/info

Chuck Lever
2024-11-20T00:21:59Z

On Wed, Nov 20, 2024 at 09:22:59AM +1100, NeilBrown wrote:
> On Wed, 20 Nov 2024, Chuck Lever wrote:
> > On Tue, Nov 19, 2024 at 11:41:30AM +1100, NeilBrown wrote:
> > > Each client now reports the number of slots allocated in each session.
> >
> > Can this file also report the target slot count? Ie, is the server
> > matching the client's requested slot count, or is it over or under
> > by some number?
>
> I could. Would you like to suggest a syntax?
> Usually the numbers would be the same except for short transition
> periods, so I'm not convinced of the value.

That's precisely the kind of situation I would like to be able
catch -- the two are unequal longer than expected.

> Currently if the target is reduced while the client is idle there can be
> a longer delay before the slots are actually freed, but I think 2
> lease-renewal SEQUENCE ops would do it. If/when we add use of the
> CB_RECALL_SLOT callback the delay should disappear.
>
> > Would it be useful for a server tester or administrator to poke a
> > target slot count value into this file and watch the machinery
> > adjust?
>
> Maybe. By echo 3 > drop_caches does a pretty good job. I don't see
> that we need more.

Fair enough.

--
Chuck Lever