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authorYuchung Cheng <ycheng@google.com>2017-12-13 00:10:40 +0300
committerDavid S. Miller <davem@davemloft.net>2017-12-13 23:51:12 +0300
commit7268586baa530312041e597b518b5c6a05110df1 (patch)
tree09075b8fb35fcc5ad90f744345d1582fe7d62f4c /Documentation/networking
parent8a83c5d7969b8433584e3cf658a8d76c4dc37f4d (diff)
downloadlinux-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 'Documentation/networking')
-rw-r--r--Documentation/networking/ip-sysctl.txt1
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 46c7e1085efc..3f2c40d8e6aa 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -606,6 +606,7 @@ tcp_fastopen_blackhole_timeout_sec - INTEGER
This time period will grow exponentially when more blackhole issues
get detected right after Fastopen is re-enabled and will reset to
initial value when the blackhole issue goes away.
+ 0 to disable the blackhole detection.
By default, it is set to 1hr.
tcp_syn_retries - INTEGER