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| author | Jiayuan Chen <jiayuan.chen@linux.dev> | 2025-04-07 17:21:20 +0300 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-04-10 05:58:59 +0300 |
| commit | 7683167196bd727ad5f3c3fc6a9ca70f54520a81 (patch) | |
| tree | b23f8bd01cef02d08a82bb8270164f7bfff1789d /net/core | |
| parent | 727d00a51f1010a87ad283ecd4780d9c38a2a691 (diff) | |
| download | linux-7683167196bd727ad5f3c3fc6a9ca70f54520a81.tar.xz | |
bpf, sockmap: Fix data lost during EAGAIN retries
We call skb_bpf_redirect_clear() to clean _sk_redir before handling skb in
backlog, but when sk_psock_handle_skb() return EAGAIN due to sk_rcvbuf
limit, the redirect info in _sk_redir is not recovered.
Fix skb redir loss during EAGAIN retries by restoring _sk_redir
information using skb_bpf_set_redir().
Before this patch:
'''
./bench sockmap -c 2 -p 1 -a --rx-verdict-ingress
Setting up benchmark 'sockmap'...
create socket fd c1:13 p1:14 c2:15 p2:16
Benchmark 'sockmap' started.
Send Speed 1343.172 MB/s, BPF Speed 1343.238 MB/s, Rcv Speed 65.271 MB/s
Send Speed 1352.022 MB/s, BPF Speed 1352.088 MB/s, Rcv Speed 0 MB/s
Send Speed 1354.105 MB/s, BPF Speed 1354.105 MB/s, Rcv Speed 0 MB/s
Send Speed 1355.018 MB/s, BPF Speed 1354.887 MB/s, Rcv Speed 0 MB/s
'''
Due to the high send rate, the RX processing path may frequently hit the
sk_rcvbuf limit. Once triggered, incorrect _sk_redir will cause the flow
to mistakenly enter the "!ingress" path, leading to send failures.
(The Rcv speed depends on tcp_rmem).
After this patch:
'''
./bench sockmap -c 2 -p 1 -a --rx-verdict-ingress
Setting up benchmark 'sockmap'...
create socket fd c1:13 p1:14 c2:15 p2:16
Benchmark 'sockmap' started.
Send Speed 1347.236 MB/s, BPF Speed 1347.367 MB/s, Rcv Speed 65.402 MB/s
Send Speed 1353.320 MB/s, BPF Speed 1353.320 MB/s, Rcv Speed 65.536 MB/s
Send Speed 1353.186 MB/s, BPF Speed 1353.121 MB/s, Rcv Speed 65.536 MB/s
'''
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://lore.kernel.org/r/20250407142234.47591-2-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/skmsg.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/skmsg.c b/net/core/skmsg.c index 0ddc4c718833..29cb5ffd56c0 100644 --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -680,7 +680,8 @@ static void sk_psock_backlog(struct work_struct *work) if (ret <= 0) { if (ret == -EAGAIN) { sk_psock_skb_state(psock, state, len, off); - + /* Restore redir info we cleared before */ + skb_bpf_set_redir(skb, psock->sk, ingress); /* Delay slightly to prioritize any * other work that might be here. */ |