tree 70ac2c3d5f22c02974a2ff5b0957cff79c3c21bd
parent 739de3f1191e01c10b3d7bb7ad79686156a05909
author Amaury Denoyelle <adenoyelle@haproxy.com> 1680711471 +0200
committer Amaury Denoyelle <adenoyelle@haproxy.com> 1681830574 +0200

MAJOR: quic: support thread balancing on accept

Before this patch, QUIC protocol used a custom add_listener callback.
This was because a quic_conn instance was allocated before accept. Its
thread affinity was fixed and could not be changed after. The thread was
derived itself from the CID selected by the client which prevent an even
repartition of QUIC connections on multiple threads.

A series of patches was introduced with a lot of changes. The most
important ones :
* removal of affinity between an encoded CID and a thread
* possibility to rebind a quic_conn on a new thread

Thanks to this, it's possible to suppress the custom add_listener
callback. Accept is conducted for QUIC protocol as with the others. A
less loaded thread is selected on listener_accept() and the connection
stack is bind on it. This operation implies that quic_conn instance is
moved to the new thread using the set_affinity QUIC protocol callback.

To reactivate quic_conn instance after thread rebind,
qc_finalize_affinity_rebind() is called after accept on the new thread
by qc_xprt_start() through accept_queue_process() / session_accept_fd().

This should be backported up to 2.7 after a period of observation.