Re: [ewg] nfsrdma fails to write big file,

Tom Tucker
2010-02-24T22:13:44Z

Roland Dreier wrote:
> > + /*
> > + * Add room for frmr register and invalidate WRs
> > + * Requests sometimes have two chunks, each chunk
> > + * requires to have different frmr. The safest
> > + * WRs required are max_send_wr * 6; however, we
> > + * get send completions and poll fast enough, it
> > + * is pretty safe to have max_send_wr * 4.
> > + */
> > + ep->rep_attr.cap.max_send_wr *= 4;
>
> Seems like a bad design if there is a possibility of work queue
> overflow; if you're counting on events occurring in a particular order
> or completions being handled "fast enough", then your design is going to
> fail in some high load situations, which I don't think you want.
>
>

I agree. It's basically a time bomb. A bump in the work flow and you'll
overflow the CQ.

Thanks for finding the bug though Vu.
> - R.