Re: [PATCH net-next 3/4] net: call prot->release_cb() when processing backlog

On Tue, Sep 12, 2023 at 6:59 PM Paolo Abeni [off-list ref] wrote:

On Mon, 2023-09-11 at 17:05 +0000, Eric Dumazet wrote:

quoted

__sk_flush_backlog() / sk_flush_backlog() are used
when TCP recvmsg()/sendmsg() process large chunks,
to not let packets in the backlog too long.

It makes sense to call tcp_release_cb() to also
process actions held in sk->sk_tsq_flags for smoother
scheduling.

Signed-off-by: Eric Dumazet <redacted>
---
 net/core/sock.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/sock.c b/net/core/sock.c
index 21610e3845a5042f7c648ccb3e0d90126df20a0b..bb89b88bc1e8a042c4ee40b3c8345dc58cb1b369 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c

@@ -3001,6 +3001,9 @@ void __sk_flush_backlog(struct sock *sk)
 {
      spin_lock_bh(&sk->sk_lock.slock);
      __release_sock(sk);
+
+     if (sk->sk_prot->release_cb)
+             sk->sk_prot->release_cb(sk);

Out of sheer curiosity, I'm wondering if adding an
indirect_call_wrapper here could make any difference?

I guess not much, and in any case it could be a follow-up.

I think it would make sense, particularly from release_sock()

We have such a change in our kernel, for some reason its author never
upstreamed it :/