| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.15 172/177] Revert "xsk: Do not sleep in poll() when need_wakeup set" | Date | Mon, 20 Dec 2021 15:35:22 +0100 |
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From: Magnus Karlsson <magnus.karlsson@intel.com>
commit 0706a78f31c4217ca144f630063ec9561a21548d upstream.
This reverts commit bd0687c18e635b63233dc87f38058cd728802ab4.
This patch causes a Tx only workload to go to sleep even when it does not have to, leading to misserable performance in skb mode. It fixed one rare problem but created a much worse one, so this need to be reverted while I try to craft a proper solution to the original problem.
Fixes: bd0687c18e63 ("xsk: Do not sleep in poll() when need_wakeup set") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20211217145646.26449-1-magnus.karlsson@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/xdp/xsk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -692,6 +692,8 @@ static __poll_t xsk_poll(struct file *fi 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; @@ -703,8 +705,6 @@ static __poll_t xsk_poll(struct file *fi else /* Poll needs to drive Tx also in copy mode */ __xsk_sendmsg(sk); - } else { - sock_poll_wait(file, sock, wait); } if (xs->rx && !xskq_prod_is_empty(xs->rx))
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