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Commit 3ee94372 authored by Neil Horman's avatar Neil Horman Committed by David S. Miller
Browse files

ipv4: remove ip_rt_secret timer (v4) 



A while back there was a discussion regarding the rt_secret_interval timer.
Given that we've had the ability to do emergency route cache rebuilds for awhile
now, based on a statistical analysis of the various hash chain lengths in the
cache, the use of the flush timer is somewhat redundant.  This patch removes the
rt_secret_interval sysctl, allowing us to rely solely on the statistical
analysis mechanism to determine the need for route cache flushes.

Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Acked-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e0e33280

include/net/netns/ipv4.h

+0 −1
Original line number Diff line number Diff line
@@ -55,7 +55,6 @@ struct netns_ipv4 { 
	int sysctl_rt_cache_rebuild_count;

	int current_rt_cache_rebuild_count;



	struct timer_list rt_secret_timer;

	atomic_t rt_genid;



#ifdef CONFIG_IP_MROUTE

kernel/sysctl_binary.c

+0 −1
Original line number Diff line number Diff line
@@ -224,7 +224,6 @@ static const struct bin_table bin_net_ipv4_route_table[] = { 
	{ CTL_INT,	NET_IPV4_ROUTE_MTU_EXPIRES,		"mtu_expires" },

	{ CTL_INT,	NET_IPV4_ROUTE_MIN_PMTU,		"min_pmtu" },

	{ CTL_INT,	NET_IPV4_ROUTE_MIN_ADVMSS,		"min_adv_mss" },

	{ CTL_INT,	NET_IPV4_ROUTE_SECRET_INTERVAL,		"secret_interval" },

	{}

};

net/ipv4/route.c

+8 −100
Original line number Diff line number Diff line
@@ -129,7 +129,6 @@ static int ip_rt_gc_elasticity __read_mostly = 8; 
static int ip_rt_mtu_expires __read_mostly	= 10 * 60 * HZ;

static int ip_rt_min_pmtu __read_mostly		= 512 + 20 + 20;

static int ip_rt_min_advmss __read_mostly	= 256;

static int ip_rt_secret_interval __read_mostly	= 10 * 60 * HZ;

static int rt_chain_length_max __read_mostly	= 20;



static struct delayed_work expires_work;
@@ -918,32 +917,11 @@ void rt_cache_flush_batch(void) 
	rt_do_flush(!in_softirq());

}



/*

 * We change rt_genid and let gc do the cleanup

 */

static void rt_secret_rebuild(unsigned long __net)

{

	struct net *net = (struct net *)__net;

	rt_cache_invalidate(net);

	mod_timer(&net->ipv4.rt_secret_timer, jiffies + ip_rt_secret_interval);

}



static void rt_secret_rebuild_oneshot(struct net *net)

{

	del_timer_sync(&net->ipv4.rt_secret_timer);

	rt_cache_invalidate(net);

	if (ip_rt_secret_interval)

		mod_timer(&net->ipv4.rt_secret_timer, jiffies + ip_rt_secret_interval);

}



static void rt_emergency_hash_rebuild(struct net *net)

{

	if (net_ratelimit()) {

	if (net_ratelimit())

		printk(KERN_WARNING "Route hash chain too long!\n");

		printk(KERN_WARNING "Adjust your secret_interval!\n");

	}



	rt_secret_rebuild_oneshot(net);

	rt_cache_invalidate(net);

}



/*
@@ -3101,48 +3079,6 @@ static int ipv4_sysctl_rtcache_flush(ctl_table *__ctl, int write, 
	return -EINVAL;

}



static void rt_secret_reschedule(int old)

{

	struct net *net;

	int new = ip_rt_secret_interval;

	int diff = new - old;



	if (!diff)

		return;



	rtnl_lock();

	for_each_net(net) {

		int deleted = del_timer_sync(&net->ipv4.rt_secret_timer);

		long time;



		if (!new)

			continue;



		if (deleted) {

			time = net->ipv4.rt_secret_timer.expires - jiffies;



			if (time <= 0 || (time += diff) <= 0)

				time = 0;

		} else

			time = new;



		mod_timer(&net->ipv4.rt_secret_timer, jiffies + time);

	}

	rtnl_unlock();

}



static int ipv4_sysctl_rt_secret_interval(ctl_table *ctl, int write,

					  void __user *buffer, size_t *lenp,

					  loff_t *ppos)

{

	int old = ip_rt_secret_interval;

	int ret = proc_dointvec_jiffies(ctl, write, buffer, lenp, ppos);



	rt_secret_reschedule(old);



	return ret;

}



static ctl_table ipv4_route_table[] = {

	{

		.procname	= "gc_thresh",
@@ -3251,13 +3187,6 @@ static ctl_table ipv4_route_table[] = { 
		.mode		= 0644,

		.proc_handler	= proc_dointvec,

	},

	{

		.procname	= "secret_interval",

		.data		= &ip_rt_secret_interval,

		.maxlen		= sizeof(int),

		.mode		= 0644,

		.proc_handler	= ipv4_sysctl_rt_secret_interval,

	},

	{ }

};
@@ -3336,34 +3265,15 @@ static __net_initdata struct pernet_operations sysctl_route_ops = { 
};

#endif





static __net_init int rt_secret_timer_init(struct net *net)

static __net_init int rt_genid_init(struct net *net)

{

	atomic_set(&net->ipv4.rt_genid,

			(int) ((num_physpages ^ (num_physpages>>8)) ^

			(jiffies ^ (jiffies >> 7))));



	net->ipv4.rt_secret_timer.function = rt_secret_rebuild;

	net->ipv4.rt_secret_timer.data = (unsigned long)net;

	init_timer_deferrable(&net->ipv4.rt_secret_timer);



	if (ip_rt_secret_interval) {

		net->ipv4.rt_secret_timer.expires =

			jiffies + net_random() % ip_rt_secret_interval +

			ip_rt_secret_interval;

		add_timer(&net->ipv4.rt_secret_timer);

	}

	get_random_bytes(&net->ipv4.rt_genid,

			 sizeof(net->ipv4.rt_genid));

	return 0;

}



static __net_exit void rt_secret_timer_exit(struct net *net)

{

	del_timer_sync(&net->ipv4.rt_secret_timer);

}



static __net_initdata struct pernet_operations rt_secret_timer_ops = {

	.init = rt_secret_timer_init,

	.exit = rt_secret_timer_exit,

static __net_initdata struct pernet_operations rt_genid_ops = {

	.init = rt_genid_init,

};
@@ -3424,9 +3334,6 @@ int __init ip_rt_init(void) 
	schedule_delayed_work(&expires_work,

		net_random() % ip_rt_gc_interval + ip_rt_gc_interval);



	if (register_pernet_subsys(&rt_secret_timer_ops))

		printk(KERN_ERR "Unable to setup rt_secret_timer\n");



	if (ip_rt_proc_init())

		printk(KERN_ERR "Unable to create route proc files\n");

#ifdef CONFIG_XFRM
@@ -3438,6 +3345,7 @@ int __init ip_rt_init(void) 
#ifdef CONFIG_SYSCTL

	register_pernet_subsys(&sysctl_route_ops);

#endif

	register_pernet_subsys(&rt_genid_ops);

	return rc;

}