diff options
| author | Yuchung Cheng <ycheng@google.com> | 2017-12-13 00:10:40 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-12-13 23:51:12 +0300 |
| commit | 7268586baa530312041e597b518b5c6a05110df1 (patch) | |
| tree | 09075b8fb35fcc5ad90f744345d1582fe7d62f4c /net/ipv4/tcp_metrics.c | |
| parent | 8a83c5d7969b8433584e3cf658a8d76c4dc37f4d (diff) | |
| download | linux-7268586baa530312041e597b518b5c6a05110df1.tar.xz | |
tcp: pause Fast Open globally after third consecutive timeout
Prior to this patch, active Fast Open is paused on a specific
destination IP address if the previous connections to the
IP address have experienced recurring timeouts . But recent
experiments by Microsoft (https://goo.gl/cykmn7) and Mozilla
browsers indicate the isssue is often caused by broken middle-boxes
sitting close to the client. Therefore it is much better user
experience if Fast Open is disabled out-right globally to avoid
experiencing further timeouts on connections toward other
destinations.
This patch changes the destination-IP disablement to global
disablement if a connection experiencing recurring timeouts
or aborts due to timeout. Repeated incidents would still
exponentially increase the pause time, starting from an hour.
This is extremely conservative but an unfortunate compromise to
minimize bad experience due to broken middle-boxes.
Reported-by: Dragana Damjanovic <ddamjanovic@mozilla.com>
Reported-by: Patrick McManus <mcmanus@ducksong.com>
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Wei Wang <weiwan@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_metrics.c')
| -rw-r--r-- | net/ipv4/tcp_metrics.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index 7097f92d16e5..759e6bc8327b 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -546,8 +546,7 @@ bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst) static DEFINE_SEQLOCK(fastopen_seqlock); void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, - struct tcp_fastopen_cookie *cookie, - int *syn_loss, unsigned long *last_syn_loss) + struct tcp_fastopen_cookie *cookie) { struct tcp_metrics_block *tm; @@ -564,8 +563,6 @@ void tcp_fastopen_cache_get(struct sock *sk, u16 *mss, *cookie = tfom->cookie; if (cookie->len <= 0 && tfom->try_exp == 1) cookie->exp = true; - *syn_loss = tfom->syn_loss; - *last_syn_loss = *syn_loss ? tfom->last_syn_loss : 0; } while (read_seqretry(&fastopen_seqlock, seq)); } rcu_read_unlock(); |