diff options
| author | Laurence Rowe <laurencerowe@gmail.com> | 2026-04-02 23:49:18 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-04-07 04:29:01 +0300 |
| commit | 98f28d8d6e5a5ed058dd37854c19e9b3bae72eff (patch) | |
| tree | 7e5f15a43efa854a405bdcf30e9ee1c113f609e8 | |
| parent | c8eee00c0fef5f709b9114be432d7b3afebb4c0a (diff) | |
| download | linux-98f28d8d6e5a5ed058dd37854c19e9b3bae72eff.tar.xz | |
vsock: avoid timeout for non-blocking accept() with empty backlog
A common pattern in epoll network servers is to eagerly accept all
pending connections from the non-blocking listening socket after
epoll_wait indicates the socket is ready by calling accept in a loop
until EAGAIN is returned indicating that the backlog is empty.
Scheduling a timeout for a non-blocking accept with an empty backlog
meant AF_VSOCK sockets used by epoll network servers incurred hundreds
of microseconds of additional latency per accept loop compared to
AF_INET or AF_UNIX sockets.
Signed-off-by: Laurence Rowe <laurencerowe@gmail.com>
Reviewed-by: Bobby Eshleman <bobbyeshleman@meta.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://patch.msgid.link/20260402204918.130395-1-laurencerowe@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/vmw_vsock/af_vsock.c | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index e4756604d50b..b8794ea0f01e 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -1864,10 +1864,10 @@ static int vsock_accept(struct socket *sock, struct socket *newsock, * created upon connection establishment. */ timeout = sock_rcvtimeo(listener, arg->flags & O_NONBLOCK); - prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE); while ((connected = vsock_dequeue_accept(listener)) == NULL && - listener->sk_err == 0) { + listener->sk_err == 0 && timeout != 0) { + prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE); release_sock(listener); timeout = schedule_timeout(timeout); finish_wait(sk_sleep(listener), &wait); @@ -1876,17 +1876,14 @@ static int vsock_accept(struct socket *sock, struct socket *newsock, if (signal_pending(current)) { err = sock_intr_errno(timeout); goto out; - } else if (timeout == 0) { - err = -EAGAIN; - goto out; } - - prepare_to_wait(sk_sleep(listener), &wait, TASK_INTERRUPTIBLE); } - finish_wait(sk_sleep(listener), &wait); - if (listener->sk_err) + if (listener->sk_err) { err = -listener->sk_err; + } else if (!connected) { + err = -EAGAIN; + } if (connected) { sk_acceptq_removed(listener); |