[PATCH v2 nf-next] ipvs: Move defense_work and est_reload_work to system_dfl_long_wq

[PATCH v2 nf-next] ipvs: Move defense_work and est_reload_work to system_dfl_long_wq

[Ismael Luceno]

Under synflood conditions binding these handlers to system_long_wq may
pin them to a saturated CPU.

We've observed improved throughtput on a DPDK/VPP application with this
change, which we attribute to the reduced context switching.

Neither handler has per-CPU data dependencies nor cache locality
requirements that would prevent this change.

Signed-off-by: Ismael Luceno <iluceno@suse.de>
---
CC: Marco Crivellari <marco.crivellari@suse.com>
CC: Tejun Heo <tj@kernel.org>

Changes since v1:
* Rebased on nf-next
* Reworded commit message

 net/netfilter/ipvs/ip_vs_ctl.c | 6 +++---
 net/netfilter/ipvs/ip_vs_est.c | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index bcf40b8c41cf..d7e669efab4d 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -235,7 +235,7 @@ #define DEFENSE_TIMER_PERIOD	1*HZ
 	update_defense_level(ipvs);
 	if (atomic_read(&ipvs->dropentry))
 		ip_vs_random_dropentry(ipvs);
-	queue_delayed_work(system_long_wq, &ipvs->defense_work,
+	queue_delayed_work(system_dfl_long_wq, &ipvs->defense_work,
 			   DEFENSE_TIMER_PERIOD);
 }
 #endif
@@ -290,7 +290,7 @@ #define DEFENSE_TIMER_PERIOD	1*HZ
 	atomic_set(&ipvs->est_genid_done, genid);
 
 	if (repeat)
-		queue_delayed_work(system_long_wq, &ipvs->est_reload_work,
+		queue_delayed_work(system_dfl_long_wq, &ipvs->est_reload_work,
 				   delay);
 
 unlock:
@@ -5126,7 +5126,7 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
 		goto err;
 
 	/* Schedule defense work */
-	queue_delayed_work(system_long_wq, &ipvs->defense_work,
+	queue_delayed_work(system_dfl_long_wq, &ipvs->defense_work,
 			   DEFENSE_TIMER_PERIOD);
 
 	return 0;
diff --git a/net/netfilter/ipvs/ip_vs_est.c b/net/netfilter/ipvs/ip_vs_est.c
index ab09f5182951..78964aa861e9 100644
--- a/net/netfilter/ipvs/ip_vs_est.c
+++ b/net/netfilter/ipvs/ip_vs_est.c
@@ -243,7 +243,7 @@ #define pr_fmt(fmt) "IPVS: " fmt
 	/* Bump the kthread configuration genid if stopping is requested */
 	if (restart)
 		atomic_inc(&ipvs->est_genid);
-	queue_delayed_work(system_long_wq, &ipvs->est_reload_work, 0);
+	queue_delayed_work(system_dfl_long_wq, &ipvs->est_reload_work, 0);
 }
 
 /* Start kthread task with current configuration */

Re: [PATCH v2 nf-next] ipvs: Move defense_work and est_reload_work to system_dfl_long_wq

[Ismael Luceno]

Link: https://lore.kernel.org/all/20260317140100.24993-2-iluceno@suse.de/

Re: [PATCH v2 nf-next] ipvs: Move defense_work and est_reload_work to system_dfl_long_wq

[Julian Anastasov]

	Hello,

On Thu, 2 Jul 2026, Ismael Luceno wrote:

> Under synflood conditions binding these handlers to system_long_wq may
> pin them to a saturated CPU.
> 
> We've observed improved throughtput on a DPDK/VPP application with this
> change, which we attribute to the reduced context switching.
> 
> Neither handler has per-CPU data dependencies nor cache locality
> requirements that would prevent this change.
> 
> Signed-off-by: Ismael Luceno <iluceno@suse.de>

	Looks good to me, thanks!

Acked-by: Julian Anastasov <ja@ssi.bg>

> ---
> CC: Marco Crivellari <marco.crivellari@suse.com>
> CC: Tejun Heo <tj@kernel.org>
> 
> Changes since v1:
> * Rebased on nf-next
> * Reworded commit message
> 
>  net/netfilter/ipvs/ip_vs_ctl.c | 6 +++---
>  net/netfilter/ipvs/ip_vs_est.c | 2 +-
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
> index bcf40b8c41cf..d7e669efab4d 100644
> --- a/net/netfilter/ipvs/ip_vs_ctl.c
> +++ b/net/netfilter/ipvs/ip_vs_ctl.c
> @@ -235,7 +235,7 @@ #define DEFENSE_TIMER_PERIOD	1*HZ
>  	update_defense_level(ipvs);
>  	if (atomic_read(&ipvs->dropentry))
>  		ip_vs_random_dropentry(ipvs);
> -	queue_delayed_work(system_long_wq, &ipvs->defense_work,
> +	queue_delayed_work(system_dfl_long_wq, &ipvs->defense_work,
>  			   DEFENSE_TIMER_PERIOD);
>  }
>  #endif
> @@ -290,7 +290,7 @@ #define DEFENSE_TIMER_PERIOD	1*HZ
>  	atomic_set(&ipvs->est_genid_done, genid);
>  
>  	if (repeat)
> -		queue_delayed_work(system_long_wq, &ipvs->est_reload_work,
> +		queue_delayed_work(system_dfl_long_wq, &ipvs->est_reload_work,
>  				   delay);
>  
>  unlock:
> @@ -5126,7 +5126,7 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
>  		goto err;
>  
>  	/* Schedule defense work */
> -	queue_delayed_work(system_long_wq, &ipvs->defense_work,
> +	queue_delayed_work(system_dfl_long_wq, &ipvs->defense_work,
>  			   DEFENSE_TIMER_PERIOD);
>  
>  	return 0;
> diff --git a/net/netfilter/ipvs/ip_vs_est.c b/net/netfilter/ipvs/ip_vs_est.c
> index ab09f5182951..78964aa861e9 100644
> --- a/net/netfilter/ipvs/ip_vs_est.c
> +++ b/net/netfilter/ipvs/ip_vs_est.c
> @@ -243,7 +243,7 @@ #define pr_fmt(fmt) "IPVS: " fmt
>  	/* Bump the kthread configuration genid if stopping is requested */
>  	if (restart)
>  		atomic_inc(&ipvs->est_genid);
> -	queue_delayed_work(system_long_wq, &ipvs->est_reload_work, 0);
> +	queue_delayed_work(system_dfl_long_wq, &ipvs->est_reload_work, 0);
>  }
>  
>  /* Start kthread task with current configuration */

Regards

--
Julian Anastasov <ja@ssi.bg>