On Mon, Jul 31, 2017 at 04:26:08PM +0300, Michael S. Tsirkin wrote:
> I kept this around unchanged from
> ab7db91705e95ed1bba1304388936fccfa58c992. That commit had an internal
> reason not to account for that space: not enough bits to do it. No
> longer true so let's account for length exactly.
I've also observed this performance regression.
The minimal fix for me is removing the two
> if (unlikely(len > (unsigned long)ctx))
checks added in 680557c.
After digging a little more, the reason that check can fail appears to
be that add_recvbuf_mergeable sometimes includes a hole at the end,
