Re: [patch v4] infiniband: uverbs: handle large number of entries

Roland Dreier
2010-11-25T04:05:47Z

> This breaks how userspace wants to use poll, ie if you return anything
> less than what I asked for then that means there is no more work to
> do. Apps make this assumption, and is a reasonable thing to
> do. Otherwise apps need a dummy call to ibv_poll to avoid races.

OIC. forgot about that. hmm...

> So if you are worried about how many times ib_poll_cq is called then
> bound the kzalloc size and wrap the whole thing in a loop, but
> realistically I have to think the performance trade off of
> kzalloc/free vs calling ib_poll more often is not entirely obvious.

That's true... maybe doing things one at a time but avoiding the allocs
is the right tradeoff.

> Who uses this path anyhow?

AFAICT, cxgb3, cxgb4, nes, ipath and qib.

- R.