Re: [PATCH v2 0/3] Register TCP flows with epoll at creation time

[Stefano Brivio <sbrivio@redhat.com>]

On Mon, 19 Jan 2026 17:19:12 +0100
Laurent Vivier <lvivier@redhat.com> wrote:

> This series simplifies epoll registration by moving it to flow creation
> time rather than deferring it to the first event update. By registering
> sockets with epoll immediately (using events=0), the epoll control
> functions can always use EPOLL_CTL_MOD, eliminating the need to track
> whether a flow is already registered.
> 
> Patch 1 registers both splice sockets with epoll in tcp_splice_connect()
> before initiating the connection, allowing tcp_splice_epoll_ctl() to
> always use EPOLL_CTL_MOD.
> 
> Patch 2 does the same for regular TCP connections in tcp_conn_from_tap(),
> tcp_tap_conn_from_sock(), and tcp_flow_migrate_target(), simplifying
> tcp_epoll_ctl() by removing the ADD/MOD conditional logic.
> 
> Patch 3 removes EPOLLFD_ID_INVALID and related infrastructure now that
> all flows are registered at creation: flow_in_epoll(), flow_epollid_clear(),
> and the defensive checks in flow_epollfd().

Applied.

-- 
Stefano