From: Jakub Kicinski <kuba@kernel.org>
To: Eric Dumazet <edumazet@google.com>
Cc: Pengcheng Yang <yangpc@wangsu.com>,
Neal Cardwell <ncardwell@google.com>,
Yuchung Cheng <ycheng@google.com>,
David Miller <davem@davemloft.net>,
netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH net] tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN
Date: Fri, 22 Jan 2021 17:27:03 -0800 [thread overview]
Message-ID: <20210122172703.39cfff6c@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <CANn89iJoBeApn6y8k9xv_FZCGKG8n1GyXb9SKYq+LGBTp52cag@mail.gmail.com>
On Fri, 22 Jan 2021 11:53:46 +0100 Eric Dumazet wrote:
> On Fri, Jan 22, 2021 at 11:28 AM Pengcheng Yang <yangpc@wangsu.com> wrote:
> >
> > When CA_STATE is in DISORDER, the TLP timer is not set when receiving
> > an ACK (a cumulative ACK covered out-of-order data) causes CA_STATE to
> > change from DISORDER to OPEN. If the sender is app-limited, it can only
> > wait for the RTO timer to expire and retransmit.
> >
> > The reason for this is that the TLP timer is set before CA_STATE changes
> > in tcp_ack(), so we delay the time point of calling tcp_set_xmit_timer()
> > until after tcp_fastretrans_alert() returns and remove the
> > FLAG_SET_XMIT_TIMER from ack_flag when the RACK reorder timer is set.
> >
> > This commit has two additional benefits:
> > 1) Make sure to reset RTO according to RFC6298 when receiving ACK, to
> > avoid spurious RTO caused by RTO timer early expires.
> > 2) Reduce the xmit timer reschedule once per ACK when the RACK reorder
> > timer is set.
> >
> > Link: https://lore.kernel.org/netdev/1611139794-11254-1-git-send-email-yangpc@wangsu.com
> > Signed-off-by: Pengcheng Yang <yangpc@wangsu.com>
> > Cc: Neal Cardwell <ncardwell@google.com>
>
> This looks like a very nice patch, let me run packetdrill tests on it.
>
> By any chance, have you cooked a packetdrill test showing the issue
> (failing on unpatched kernel) ?
Any guidance on backporting / fixes tag? (once the packetdrill
questions are satisfied)
next prev parent reply other threads:[~2021-01-23 1:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-22 10:27 [PATCH net] tcp: fix TLP timer not set when CA_STATE changes from DISORDER to OPEN Pengcheng Yang
2021-01-22 10:53 ` Eric Dumazet
2021-01-22 14:36 ` Neal Cardwell
2021-01-22 21:02 ` Yuchung Cheng
2021-01-23 13:58 ` Pengcheng Yang
2021-01-23 19:14 ` Yuchung Cheng
2021-01-23 1:27 ` Jakub Kicinski [this message]
2021-01-23 14:47 ` Pengcheng Yang
2021-01-23 18:25 ` Neal Cardwell
2021-01-23 20:25 ` Jakub Kicinski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210122172703.39cfff6c@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com \
--to=kuba@kernel.org \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=ncardwell@google.com \
--cc=netdev@vger.kernel.org \
--cc=yangpc@wangsu.com \
--cc=ycheng@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.