* [PATCH] tcp: remove obsolete paramter sysctl_tcp_low_latency
@ 2020-12-18 6:11 lyl
2020-12-19 0:46 ` Jakub Kicinski
0 siblings, 1 reply; 5+ messages in thread
From: lyl @ 2020-12-18 6:11 UTC (permalink / raw)
To: netdev; +Cc: davem, fw, qitiepeng, liyonglong
Remove tcp_low_latency, since it is not functional After commit
e7942d0633c4 (tcp: remove prequeue support)
Signed-off-by: lyl <liyonglong@chinatelecom.cn>
---
net/ipv4/sysctl_net_ipv4.c | 10 ----------
1 file changed, 10 deletions(-)
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 3e5f4f2..d03e4c0 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -51,9 +51,6 @@
static u32 u32_max_div_HZ = UINT_MAX / HZ;
static int one_day_secs = 24 * 3600;
-/* obsolete */
-static int sysctl_tcp_low_latency __read_mostly;
-
/* Update system visible IP port range */
static void set_local_port_range(struct net *net, int range[2])
{
@@ -501,13 +498,6 @@ static int proc_fib_multipath_hash_policy(struct ctl_table *table, int write,
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
- {
- .procname = "tcp_low_latency",
- .data = &sysctl_tcp_low_latency,
- .maxlen = sizeof(int),
- .mode = 0644,
- .proc_handler = proc_dointvec
- },
#ifdef CONFIG_NETLABEL
{
.procname = "cipso_cache_enable",
--
1.8.3.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH] tcp: remove obsolete paramter sysctl_tcp_low_latency
2020-12-18 6:11 [PATCH] tcp: remove obsolete paramter sysctl_tcp_low_latency lyl
@ 2020-12-19 0:46 ` Jakub Kicinski
2021-01-07 3:08 ` lll
0 siblings, 1 reply; 5+ messages in thread
From: Jakub Kicinski @ 2020-12-19 0:46 UTC (permalink / raw)
To: lyl, Eric Dumazet; +Cc: netdev, davem, fw, qitiepeng
On Fri, 18 Dec 2020 14:11:16 +0800 lyl wrote:
> Remove tcp_low_latency, since it is not functional After commit
> e7942d0633c4 (tcp: remove prequeue support)
>
> Signed-off-by: lyl <liyonglong@chinatelecom.cn>
I don't think we can remove sysctls, even if they no longer control
the behavior of the kernel. The existence of the file itself is uAPI.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tcp: remove obsolete paramter sysctl_tcp_low_latency
2020-12-19 0:46 ` Jakub Kicinski
@ 2021-01-07 3:08 ` lll
2021-01-07 17:06 ` Jakub Kicinski
0 siblings, 1 reply; 5+ messages in thread
From: lll @ 2021-01-07 3:08 UTC (permalink / raw)
To: Jakub Kicinski, Eric Dumazet; +Cc: netdev, davem, fw
在 2020/12/19 8:46, Jakub Kicinski 写道:
> On Fri, 18 Dec 2020 14:11:16 +0800 lyl wrote:
>> Remove tcp_low_latency, since it is not functional After commit
>> e7942d0633c4 (tcp: remove prequeue support)
>>
>> Signed-off-by: lyl <liyonglong@chinatelecom.cn>
>
> I don't think we can remove sysctls, even if they no longer control
> the behavior of the kernel. The existence of the file itself is uAPI.
>
Got it. But a question: why tcp_tw_recycle can be removed totally? it is also part of uAPI
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tcp: remove obsolete paramter sysctl_tcp_low_latency
2021-01-07 3:08 ` lll
@ 2021-01-07 17:06 ` Jakub Kicinski
2021-01-07 17:45 ` Florian Westphal
0 siblings, 1 reply; 5+ messages in thread
From: Jakub Kicinski @ 2021-01-07 17:06 UTC (permalink / raw)
To: lll; +Cc: Eric Dumazet, netdev, davem, fw, soheil, ncardwell, ycheng
On Thu, 7 Jan 2021 11:08:16 +0800 lll wrote:
> 在 2020/12/19 8:46, Jakub Kicinski 写道:
> > On Fri, 18 Dec 2020 14:11:16 +0800 lyl wrote:
> >> Remove tcp_low_latency, since it is not functional After commit
> >> e7942d0633c4 (tcp: remove prequeue support)
> >>
> >> Signed-off-by: lyl <liyonglong@chinatelecom.cn>
> >
> > I don't think we can remove sysctls, even if they no longer control
> > the behavior of the kernel. The existence of the file itself is uAPI.
>
> Got it. But a question: why tcp_tw_recycle can be removed totally?
> it is also part of uAPI
Good question, perhaps with tcp_tw_recycle we wanted to make sure users
who depended on it notice removal, since the feature was broken by
design?
tcp_low_latency is an optimization, not functionality which users may
depend on.
But I may be wrong so CCing authors.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] tcp: remove obsolete paramter sysctl_tcp_low_latency
2021-01-07 17:06 ` Jakub Kicinski
@ 2021-01-07 17:45 ` Florian Westphal
0 siblings, 0 replies; 5+ messages in thread
From: Florian Westphal @ 2021-01-07 17:45 UTC (permalink / raw)
To: Jakub Kicinski
Cc: lll, Eric Dumazet, netdev, davem, fw, soheil, ncardwell, ycheng
Jakub Kicinski <kuba@kernel.org> wrote:
> > Got it. But a question: why tcp_tw_recycle can be removed totally?
> > it is also part of uAPI
>
> Good question, perhaps with tcp_tw_recycle we wanted to make sure users
> who depended on it notice removal, since the feature was broken by
> design?
>
> tcp_low_latency is an optimization, not functionality which users may
> depend on.
>
> But I may be wrong so CCing authors.
I guess it was just a case of 'noone noticed'.
I'm not sure if anyone would notice dropping lowlatency sysctl, was just
a case of 'overly careful'. Personally I'd rather have them gone so
'sysctl tcp.bla' shows if the feature exists/does something.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-01-07 17:46 UTC | newest]
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2020-12-18 6:11 [PATCH] tcp: remove obsolete paramter sysctl_tcp_low_latency lyl
2020-12-19 0:46 ` Jakub Kicinski
2021-01-07 3:08 ` lll
2021-01-07 17:06 ` Jakub Kicinski
2021-01-07 17:45 ` Florian Westphal
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