On Mon, Nov 23, 2020 at 3:11 PM Magnus Karlsson
<magnus.karlsson@xxxxxxxxx> wrote:
>
> On Wed, Nov 18, 2020 at 9:26 AM Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> wrote:
> >
> > datagram_poll will judge the current socket status (EPOLLIN, EPOLLOUT)
> > based on the traditional socket information (eg: sk_wmem_alloc), but
> > this does not apply to xsk. So this patch uses sock_poll_wait instead of
> > datagram_poll, and the mask is calculated by xsk_poll.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
> > ---
> > net/xdp/xsk.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> > index cfbec39..7f0353e 100644
> > --- a/net/xdp/xsk.c
> > +++ b/net/xdp/xsk.c
> > @@ -477,11 +477,13 @@ static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
> > static __poll_t xsk_poll(struct file *file, struct socket *sock,
> > struct poll_table_struct *wait)
> > {
> > - __poll_t mask = datagram_poll(file, sock, wait);
> > + __poll_t mask = 0;
>
> It would indeed be nice to not execute a number of tests in
> datagram_poll that will never be triggered. It will speed up things
> for sure. But we need to make sure that removing those flags that
> datagram_poll sets do not have any bad effects in the code above this.
> But let us tentatively keep this patch for the next version of the
> patch set. Just need to figure out how to solve your problem in a nice
> way first. See discussion in patch 0/3.
>
> > struct sock *sk = sock->sk;
> > struct xdp_sock *xs = xdp_sk(sk);
> > struct xsk_buff_pool *pool;
> >
> > + sock_poll_wait(file, sock, wait);
> > +
> > if (unlikely(!xsk_is_bound(xs)))
> > return mask;
> >
> > --
> > 1.8.3.1
> >
The fix looks correct and it will speed things up too as a bonus.
Please include this patch in the v2 as outlined in my answer to 0/3.
Thanks!
