* [PATCH net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge()
@ 2024-03-27 19:12 Eric Dumazet
2024-03-27 19:29 ` Kuniyuki Iwashima
2024-03-29 15:20 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 5+ messages in thread
From: Eric Dumazet @ 2024-03-27 19:12 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: netdev, eric.dumazet, Eric Dumazet
TCP ehash table is often sparsely populated.
inet_twsk_purge() spends too much time calling cond_resched().
This patch can reduce time spent in inet_twsk_purge() by 20x.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/ipv4/inet_timewait_sock.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index e8de45d34d56a507a4bdcceaccbd5707692b6c0a..b0cc07d9a568c5dc52bd29729862bcb03e5d595d 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -266,12 +266,17 @@ EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
/* Remove all non full sockets (TIME_WAIT and NEW_SYN_RECV) for dead netns */
void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
{
+ struct inet_ehash_bucket *head = &hashinfo->ehash[0];
+ unsigned int ehash_mask = hashinfo->ehash_mask;
struct hlist_nulls_node *node;
unsigned int slot;
struct sock *sk;
- for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
- struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
+ for (slot = 0; slot <= ehash_mask; slot++, head++) {
+
+ if (hlist_nulls_empty(&head->chain))
+ continue;
+
restart_rcu:
cond_resched();
rcu_read_lock();
--
2.44.0.396.g6e790dbe36-goog
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge()
2024-03-27 19:12 [PATCH net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge() Eric Dumazet
@ 2024-03-27 19:29 ` Kuniyuki Iwashima
2024-03-29 15:06 ` Jakub Kicinski
2024-03-29 15:20 ` patchwork-bot+netdevbpf
1 sibling, 1 reply; 5+ messages in thread
From: Kuniyuki Iwashima @ 2024-03-27 19:29 UTC (permalink / raw)
To: edumazet; +Cc: davem, eric.dumazet, kuba, netdev, pabeni, Kuniyuki Iwashima
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 27 Mar 2024 19:12:06 +0000
> TCP ehash table is often sparsely populated.
>
> inet_twsk_purge() spends too much time calling cond_resched().
>
> This patch can reduce time spent in inet_twsk_purge() by 20x.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Sounds good!
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
1 nit below.
> ---
> net/ipv4/inet_timewait_sock.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
> index e8de45d34d56a507a4bdcceaccbd5707692b6c0a..b0cc07d9a568c5dc52bd29729862bcb03e5d595d 100644
> --- a/net/ipv4/inet_timewait_sock.c
> +++ b/net/ipv4/inet_timewait_sock.c
> @@ -266,12 +266,17 @@ EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
> /* Remove all non full sockets (TIME_WAIT and NEW_SYN_RECV) for dead netns */
> void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
> {
> + struct inet_ehash_bucket *head = &hashinfo->ehash[0];
> + unsigned int ehash_mask = hashinfo->ehash_mask;
> struct hlist_nulls_node *node;
> unsigned int slot;
> struct sock *sk;
>
> - for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
> - struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
> + for (slot = 0; slot <= ehash_mask; slot++, head++) {
> +
unnecessary blank link here.
Thanks!
> + if (hlist_nulls_empty(&head->chain))
> + continue;
> +
> restart_rcu:
> cond_resched();
> rcu_read_lock();
> --
> 2.44.0.396.g6e790dbe36-goog
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge()
2024-03-27 19:29 ` Kuniyuki Iwashima
@ 2024-03-29 15:06 ` Jakub Kicinski
2024-03-29 15:24 ` Eric Dumazet
0 siblings, 1 reply; 5+ messages in thread
From: Jakub Kicinski @ 2024-03-29 15:06 UTC (permalink / raw)
To: Kuniyuki Iwashima; +Cc: edumazet, davem, eric.dumazet, netdev, pabeni
On Wed, 27 Mar 2024 12:29:34 -0700 Kuniyuki Iwashima wrote:
> > - for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
> > - struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
> > + for (slot = 0; slot <= ehash_mask; slot++, head++) {
> > +
>
> unnecessary blank link here.
I've seen some other core kernel contributors add empty lines after
for or if statements, so I think this is intentional. Not sure why
the empty line helps, either, TBH, but we have been letting it slide
so far.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge()
2024-03-27 19:12 [PATCH net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge() Eric Dumazet
2024-03-27 19:29 ` Kuniyuki Iwashima
@ 2024-03-29 15:20 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 5+ messages in thread
From: patchwork-bot+netdevbpf @ 2024-03-29 15:20 UTC (permalink / raw)
To: Eric Dumazet; +Cc: davem, kuba, pabeni, netdev, eric.dumazet
Hello:
This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Wed, 27 Mar 2024 19:12:06 +0000 you wrote:
> TCP ehash table is often sparsely populated.
>
> inet_twsk_purge() spends too much time calling cond_resched().
>
> This patch can reduce time spent in inet_twsk_purge() by 20x.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
>
> [...]
Here is the summary with links:
- [net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge()
https://git.kernel.org/netdev/net-next/c/50e2907ef8bb
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
* Re: [PATCH net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge()
2024-03-29 15:06 ` Jakub Kicinski
@ 2024-03-29 15:24 ` Eric Dumazet
0 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2024-03-29 15:24 UTC (permalink / raw)
To: Jakub Kicinski; +Cc: Kuniyuki Iwashima, davem, eric.dumazet, netdev, pabeni
On Fri, Mar 29, 2024 at 4:06 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Wed, 27 Mar 2024 12:29:34 -0700 Kuniyuki Iwashima wrote:
> > > - for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
> > > - struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
> > > + for (slot = 0; slot <= ehash_mask; slot++, head++) {
> > > +
> >
> > unnecessary blank link here.
>
> I've seen some other core kernel contributors add empty lines after
> for or if statements, so I think this is intentional. Not sure why
> the empty line helps, either, TBH, but we have been letting it slide
> so far.
I will delete this extra line in the following patch, thanks !
^ permalink raw reply [flat|nested] 5+ messages in thread
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2024-03-27 19:12 [PATCH net-next] tcp/dccp: bypass empty buckets in inet_twsk_purge() Eric Dumazet
2024-03-27 19:29 ` Kuniyuki Iwashima
2024-03-29 15:06 ` Jakub Kicinski
2024-03-29 15:24 ` Eric Dumazet
2024-03-29 15:20 ` patchwork-bot+netdevbpf
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