Re: [PATCH v5 bpf-next 02/11] tcp: Add num_closed_socks to struct sock_reuseport.

[Martin KaFai Lau]

On Mon, May 10, 2021 at 12:44:24PM +0900, Kuniyuki Iwashima wrote:
> As noted in the following commit, a closed listener has to hold the
> reference to the reuseport group for socket migration. This patch adds a
> field (num_closed_socks) to struct sock_reuseport to manage closed sockets
> within the same reuseport group. Moreover, this and the following commits
> introduce some helper functions to split socks[] into two sections and keep
> TCP_LISTEN and TCP_CLOSE sockets in each section. Like a double-ended
> queue, we will place TCP_LISTEN sockets from the front and TCP_CLOSE
> sockets from the end.
> 
>   TCP_LISTEN---------->       <-------TCP_CLOSE
>   +---+---+  ---  +---+  ---  +---+  ---  +---+
>   | 0 | 1 |  ...  | i |  ...  | j |  ...  | k |
>   +---+---+  ---  +---+  ---  +---+  ---  +---+
> 
>   i = num_socks - 1
>   j = max_socks - num_closed_socks
>   k = max_socks - 1
> 
> This patch also extends reuseport_add_sock() and reuseport_grow() to
> support num_closed_socks.
Acked-by: Martin KaFai Lau <kafai@xxxxxx>