Subject: Re: [RFC] net: ipv4 -- Introduce ifa limit per net

From: Cyrill Gorcunov <[email-masked]>
Date: Thu, 10 Mar 2016 18:09:20 +0300

On Thu, Mar 10, 2016 at 02:03:24PM +0300, Cyrill Gorcunov wrote:
> On Thu, Mar 10, 2016 at 01:20:18PM +0300, Cyrill Gorcunov wrote:
> > On Thu, Mar 10, 2016 at 12:16:29AM +0300, Cyrill Gorcunov wrote:
> > > 
> > > Thanks for explanation, Dave! I'll continue on this task tomorrow
> > > tryin to implement optimization you proposed.
> > 
> > OK, here are the results for the preliminary patch with conntrack running
> ...
> >  net/ipv4/devinet.c |   13 ++++++++++++-
> >  1 file changed, 12 insertions(+), 1 deletion(-)
> > 
> > Index: linux-ml.git/net/ipv4/devinet.c
> > ===================================================================
> > --- linux-ml.git.orig/net/ipv4/devinet.c
> > +++ linux-ml.git/net/ipv4/devinet.c
> > @@ -403,7 +403,18 @@ no_promotions:
> >  	   So that, this order is correct.
> >  	 */
> 
> This patch is wrong, so drop it please. I'll do another.

Here I think is a better variant. The resulst are good
enough -- 1 sec for cleanup. Does the patch look sane?
---
 net/ipv4/netfilter/nf_nat_masquerade_ipv4.c |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

Index: linux-ml.git/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
===================================================================
--- linux-ml.git.orig/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
+++ linux-ml.git/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c
@@ -108,9 +108,22 @@ static int masq_inet_event(struct notifi
 			   unsigned long event,
 			   void *ptr)
 {
-	struct net_device *dev = ((struct in_ifaddr *)ptr)->ifa_dev->dev;
+	struct in_ifaddr *ifa = ptr;
+	struct net_device *dev = ifa->ifa_dev->dev;
 	struct netdev_notifier_info info;
 
+	if (event == NETDEV_DOWN) {
+		/*
+		 * When we meet dead device which is
+		 * being released with dozeon of addresses
+		 * assigned -- we can optimize calls
+		 * to conntrack cleanups and do it only
+		 * once.
+		 */
+		if (ifa->ifa_dev->dead && ifa->ifa_next)
+			return NOTIFY_DONE;
+	}
+
 	netdev_notifier_info_init(&info, dev);
 	return masq_device_event(this, event, &info);
 }