Re: kernel NULL pointer dereference in rpcb_getport_done (2.6.29.4)

[Simon Kirby <sim@hostway.ca>]

On Mon, Aug 10, 2009 at 07:55:36PM -0400, J. Bruce Fields wrote:

> Looking back at that commit--I'm now confused about how it was meant to
> work.  In the case where the woken-up thread is waiting inside of
> svc_recv(), ->nwaking doesn't get decremented at all until the request
> is processed and svc_recv() is called again--effectively limiting the
> number of concurrent requests to 5 per pool, so, if I read the code
> correctly, likely to cause problems if your workload would benefit from
> lots of requests being able to wait on io simultaneously (e.g. if you
> have a large working set and more than 5 spindles per pool).

Yes, this box is serving about 50 TB of storage space, so there are more
than 5 spindles. :)

I can't believe others aren't all complaining about the same problem, but
I guess the loads are different.

> I'm inclined to revert the patch and take another look at Greg's
> original problem.

I'm inclined to be totally happy with that! :)

Simon-