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Commit 3dc94f93 authored by Michal Kubeček's avatar Michal Kubeček Committed by David S. Miller
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ipv6: per netns FIB garbage collection 



One of our customers observed issues with FIB6 garbage collectors
running in different network namespaces blocking each other, resulting
in soft lockups (fib6_run_gc() initiated from timer runs always in
forced mode).

Now that FIB6 walkers are separated per namespace, there is no more need
for instances of fib6_run_gc() in different namespaces blocking each
other. There is still a call to icmp6_dst_gc() which operates on shared
data but this function is protected by its own shared lock.

Signed-off-by: default avatarMichal Kubecek <mkubecek@suse.cz>
Reviewed-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9a03cd8f

include/net/netns/ipv6.h

+1 −0
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ struct netns_ipv6 { 
	struct list_head	fib6_walkers;

	struct dst_ops		ip6_dst_ops;

	rwlock_t		fib6_walker_lock;

	spinlock_t		fib6_gc_lock;

	unsigned int		 ip6_rt_gc_expire;

	unsigned long		 ip6_rt_last_gc;

#ifdef CONFIG_IPV6_MULTIPLE_TABLES

net/ipv6/ip6_fib.c

+4 −5
Original line number Diff line number Diff line
@@ -1776,16 +1776,14 @@ static int fib6_age(struct rt6_info *rt, void *arg) 
	return 0;

}



static DEFINE_SPINLOCK(fib6_gc_lock);



void fib6_run_gc(unsigned long expires, struct net *net, bool force)

{

	struct fib6_gc_args gc_args;

	unsigned long now;



	if (force) {

		spin_lock_bh(&fib6_gc_lock);

	} else if (!spin_trylock_bh(&fib6_gc_lock)) {

		spin_lock_bh(&net->ipv6.fib6_gc_lock);

	} else if (!spin_trylock_bh(&net->ipv6.fib6_gc_lock)) {

		mod_timer(&net->ipv6.ip6_fib_timer, jiffies + HZ);

		return;

	}
@@ -1804,7 +1802,7 @@ void fib6_run_gc(unsigned long expires, struct net *net, bool force) 
					+ net->ipv6.sysctl.ip6_rt_gc_interval));

	else

		del_timer(&net->ipv6.ip6_fib_timer);

	spin_unlock_bh(&fib6_gc_lock);

	spin_unlock_bh(&net->ipv6.fib6_gc_lock);

}



static void fib6_gc_timer_cb(unsigned long arg)
@@ -1816,6 +1814,7 @@ static int __net_init fib6_net_init(struct net *net) 
{

	size_t size = sizeof(struct hlist_head) * FIB6_TABLE_HASHSZ;



	spin_lock_init(&net->ipv6.fib6_gc_lock);

	rwlock_init(&net->ipv6.fib6_walker_lock);

	INIT_LIST_HEAD(&net->ipv6.fib6_walkers);

	setup_timer(&net->ipv6.ip6_fib_timer, fib6_gc_timer_cb, (unsigned long)net);