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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Kuniyuki Iwashima <kuniyu@amazon.co.jp>,
	"David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>
Cc: Benjamin Herrenschmidt <benh@amazon.com>,
	Kuniyuki Iwashima <kuni1840@gmail.com>,
	bpf@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 bpf-next 00/11] Socket migration for SO_REUSEPORT.
Date: Tue, 20 Apr 2021 18:43:36 +0200	[thread overview]
Message-ID: <67fb2df2-3703-4ce9-62d0-ba15435c5a0b@gmail.com> (raw)
In-Reply-To: <20210420154140.80034-1-kuniyu@amazon.co.jp>



On 4/20/21 5:41 PM, Kuniyuki Iwashima wrote:
> The SO_REUSEPORT option allows sockets to listen on the same port and to
> accept connections evenly. However, there is a defect in the current
> implementation [1]. When a SYN packet is received, the connection is tied
> to a listening socket. Accordingly, when the listener is closed, in-flight
> requests during the three-way handshake and child sockets in the accept
> queue are dropped even if other listeners on the same port could accept
> such connections.
> 
> This situation can happen when various server management tools restart
> server (such as nginx) processes. For instance, when we change nginx
> configurations and restart it, it spins up new workers that respect the new
> configuration and closes all listeners on the old workers, resulting in the
> in-flight ACK of 3WHS is responded by RST.
> 
> The SO_REUSEPORT option is excellent to improve scalability.

This was before the SYN processing was made lockless.

I really wonder if we still need SO_REUSEPORT for TCP ?

Eventually a new accept() system call where different threads
can express how they want to choose the children sockets would
be less invasive.

Instead of having many listeners, have one listener and eventually multiple
accept queues to improve scalability of accept() phase.


  parent reply	other threads:[~2021-04-20 16:43 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-20 15:41 [PATCH v3 bpf-next 00/11] Socket migration for SO_REUSEPORT Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 01/11] net: Introduce net.ipv4.tcp_migrate_req Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 02/11] tcp: Add num_closed_socks to struct sock_reuseport Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 03/11] tcp: Keep TCP_CLOSE sockets in the reuseport group Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 04/11] tcp: Add reuseport_migrate_sock() to select a new listener Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 05/11] tcp: Migrate TCP_ESTABLISHED/TCP_SYN_RECV sockets in accept queues Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 06/11] tcp: Migrate TCP_NEW_SYN_RECV requests at retransmitting SYN+ACKs Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 07/11] tcp: Migrate TCP_NEW_SYN_RECV requests at receiving the final ACK Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 08/11] bpf: Support BPF_FUNC_get_socket_cookie() for BPF_PROG_TYPE_SK_REUSEPORT Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 09/11] bpf: Support socket migration by eBPF Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 10/11] libbpf: Set expected_attach_type for BPF_PROG_TYPE_SK_REUSEPORT Kuniyuki Iwashima
2021-04-20 15:41 ` [PATCH v3 bpf-next 11/11] bpf: Test BPF_SK_REUSEPORT_SELECT_OR_MIGRATE Kuniyuki Iwashima
2021-04-20 22:57   ` Andrii Nakryiko
2021-04-21 11:34     ` Kuniyuki Iwashima
2021-04-20 16:43 ` Eric Dumazet [this message]
2021-04-21 11:30   ` [PATCH v3 bpf-next 00/11] Socket migration for SO_REUSEPORT Kuniyuki Iwashima

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