* [PATCH net-next v3] tcp: enable mid stream window clamp
@ 2021-08-25 21:01 Neil Spring
2021-08-26 19:11 ` Yuchung Cheng
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Neil Spring @ 2021-08-25 21:01 UTC (permalink / raw)
To: davem, edumazet
Cc: yoshfuji, dsahern, kuba, netdev, ncardwell, ycheng, Neil Spring
The TCP_WINDOW_CLAMP socket option is defined in tcp(7) to "Bound the size
of the advertised window to this value." Window clamping is distributed
across two variables, window_clamp ("Maximal window to advertise" in
tcp.h) and rcv_ssthresh ("Current window clamp").
This patch updates the function where the window clamp is set to also
reduce the current window clamp, rcv_sshthresh, if needed. With this,
setting the TCP_WINDOW_CLAMP option has the documented effect of limiting
the window.
Signed-off-by: Neil Spring <ntspring@fb.com>
---
v2: - fix email formatting
v3: - address comments by setting rcv_ssthresh based on prior window
net/ipv4/tcp.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f931def6302e..e8b48df73c85 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3338,6 +3338,7 @@ int tcp_set_window_clamp(struct sock *sk, int val)
} else {
tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
SOCK_MIN_RCVBUF / 2 : val;
+ tp->rcv_ssthresh = min(tp->rcv_wnd, tp->window_clamp);
}
return 0;
}
--
2.30.2
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH net-next v3] tcp: enable mid stream window clamp
2021-08-25 21:01 [PATCH net-next v3] tcp: enable mid stream window clamp Neil Spring
@ 2021-08-26 19:11 ` Yuchung Cheng
2021-08-26 19:32 ` Eric Dumazet
2021-08-26 22:51 ` Eric Dumazet
2021-08-27 2:00 ` patchwork-bot+netdevbpf
2 siblings, 1 reply; 5+ messages in thread
From: Yuchung Cheng @ 2021-08-26 19:11 UTC (permalink / raw)
To: Neil Spring; +Cc: davem, edumazet, yoshfuji, dsahern, kuba, netdev, ncardwell
On Wed, Aug 25, 2021 at 2:02 PM Neil Spring <ntspring@fb.com> wrote:
>
> The TCP_WINDOW_CLAMP socket option is defined in tcp(7) to "Bound the size
> of the advertised window to this value." Window clamping is distributed
> across two variables, window_clamp ("Maximal window to advertise" in
> tcp.h) and rcv_ssthresh ("Current window clamp").
>
> This patch updates the function where the window clamp is set to also
> reduce the current window clamp, rcv_sshthresh, if needed. With this,
> setting the TCP_WINDOW_CLAMP option has the documented effect of limiting
> the window.
This patch looks like a bug-fix so it should be applied to net not net-next?
>
> Signed-off-by: Neil Spring <ntspring@fb.com>
> ---
> v2: - fix email formatting
>
> v3: - address comments by setting rcv_ssthresh based on prior window
>
> net/ipv4/tcp.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index f931def6302e..e8b48df73c85 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -3338,6 +3338,7 @@ int tcp_set_window_clamp(struct sock *sk, int val)
> } else {
> tp->window_clamp = val < SOCK_MIN_RCVBUF / 2 ?
> SOCK_MIN_RCVBUF / 2 : val;
> + tp->rcv_ssthresh = min(tp->rcv_wnd, tp->window_clamp);
> }
> return 0;
> }
> --
> 2.30.2
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next v3] tcp: enable mid stream window clamp
2021-08-26 19:11 ` Yuchung Cheng
@ 2021-08-26 19:32 ` Eric Dumazet
0 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2021-08-26 19:32 UTC (permalink / raw)
To: Yuchung Cheng
Cc: Neil Spring, David Miller, Hideaki YOSHIFUJI, David Ahern,
Jakub Kicinski, netdev, Neal Cardwell
On Thu, Aug 26, 2021 at 12:11 PM Yuchung Cheng <ycheng@google.com> wrote:
>
> On Wed, Aug 25, 2021 at 2:02 PM Neil Spring <ntspring@fb.com> wrote:
> >
> > The TCP_WINDOW_CLAMP socket option is defined in tcp(7) to "Bound the size
> > of the advertised window to this value." Window clamping is distributed
> > across two variables, window_clamp ("Maximal window to advertise" in
> > tcp.h) and rcv_ssthresh ("Current window clamp").
> >
> > This patch updates the function where the window clamp is set to also
> > reduce the current window clamp, rcv_sshthresh, if needed. With this,
> > setting the TCP_WINDOW_CLAMP option has the documented effect of limiting
> > the window.
> This patch looks like a bug-fix so it should be applied to net not net-next?
It seems TCP_WINDOW_CLAMP never worked in this context, not sure
if any application was expecting it to work.
Note that if we target net tree, we would like a Fixes: tag.
I will give my SOB a bit later in the day, I have to run some errands.
Thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next v3] tcp: enable mid stream window clamp
2021-08-25 21:01 [PATCH net-next v3] tcp: enable mid stream window clamp Neil Spring
2021-08-26 19:11 ` Yuchung Cheng
@ 2021-08-26 22:51 ` Eric Dumazet
2021-08-27 2:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2021-08-26 22:51 UTC (permalink / raw)
To: Neil Spring, davem, edumazet
Cc: yoshfuji, dsahern, kuba, netdev, ncardwell, ycheng
On 8/25/21 2:01 PM, Neil Spring wrote:
> The TCP_WINDOW_CLAMP socket option is defined in tcp(7) to "Bound the size
> of the advertised window to this value." Window clamping is distributed
> across two variables, window_clamp ("Maximal window to advertise" in
> tcp.h) and rcv_ssthresh ("Current window clamp").
>
> This patch updates the function where the window clamp is set to also
> reduce the current window clamp, rcv_sshthresh, if needed. With this,
> setting the TCP_WINDOW_CLAMP option has the documented effect of limiting
> the window.
>
> Signed-off-by: Neil Spring <ntspring@fb.com>
> ---
> v2: - fix email formatting
>
> v3: - address comments by setting rcv_ssthresh based on prior window
>
SGTM, thanks.
Signed-off-by: Eric Dumazet <edumazet@google.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next v3] tcp: enable mid stream window clamp
2021-08-25 21:01 [PATCH net-next v3] tcp: enable mid stream window clamp Neil Spring
2021-08-26 19:11 ` Yuchung Cheng
2021-08-26 22:51 ` Eric Dumazet
@ 2021-08-27 2:00 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+netdevbpf @ 2021-08-27 2:00 UTC (permalink / raw)
To: Neil Spring
Cc: davem, edumazet, yoshfuji, dsahern, kuba, netdev, ncardwell, ycheng
Hello:
This patch was applied to netdev/net-next.git (refs/heads/master):
On Wed, 25 Aug 2021 14:01:17 -0700 you wrote:
> The TCP_WINDOW_CLAMP socket option is defined in tcp(7) to "Bound the size
> of the advertised window to this value." Window clamping is distributed
> across two variables, window_clamp ("Maximal window to advertise" in
> tcp.h) and rcv_ssthresh ("Current window clamp").
>
> This patch updates the function where the window clamp is set to also
> reduce the current window clamp, rcv_sshthresh, if needed. With this,
> setting the TCP_WINDOW_CLAMP option has the documented effect of limiting
> the window.
>
> [...]
Here is the summary with links:
- [net-next,v3] tcp: enable mid stream window clamp
https://git.kernel.org/netdev/net-next/c/3aa7857fe1d7
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-08-27 2:00 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-25 21:01 [PATCH net-next v3] tcp: enable mid stream window clamp Neil Spring
2021-08-26 19:11 ` Yuchung Cheng
2021-08-26 19:32 ` Eric Dumazet
2021-08-26 22:51 ` Eric Dumazet
2021-08-27 2:00 ` patchwork-bot+netdevbpf
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