From: Andi Kleen <andi@firstfloor.org>
To: jheffner@psc.edu, netdev@vger.kernel.org
Subject: No pmtu probing on retransmits?
Date: Sun, 3 Feb 2008 13:37:19 +0100 [thread overview]
Message-ID: <20080203123719.GA3323@basil.nowhere.org> (raw)
Hallo,
While looking for something else in tcp_output.c I noticed that
MTU probing seems to be only done in tcp_write_xmit (when
packets come directly from process context), but not via the timer
driven timer retransmit path (tcp_retransmit_skb). Is that intentional?
It looks quite weird. I would normally assume PMTU blackholes get usually
detected on retransmit timeouts. Or do I miss something?
You seem to have assumed interrupt context at least
because tcp_mtu_probe() uses GFP_ATOMIC which is only needed for
interrupts. Currently it is only called in process context I think.
-Andi
next reply other threads:[~2008-02-03 12:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-03 12:37 Andi Kleen [this message]
2008-02-03 14:04 ` No pmtu probing on retransmits? John Heffner
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