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Commit e7f13329 authored by Pravin B Shelar's avatar Pravin B Shelar Committed by Jesse Gross
Browse files

openvswitch: Move flow table rehashing to flow install. 



Rehashing in ovs-workqueue can cause ovs-mutex lock contentions
in case of heavy flow setups where both needs ovs-mutex.  So by
moving rehashing to flow-setup we can eliminate contention.
This also simplify ovs locking and reduces dependence on
workqueue.

Signed-off-by: default avatarPravin B Shelar <pshelar@nicira.com>
Signed-off-by: default avatarJesse Gross <jesse@nicira.com>
parent 272b98c6

net/openvswitch/datapath.c

+11 −39
Original line number Diff line number Diff line
@@ -60,8 +60,6 @@ 




#define REHASH_FLOW_INTERVAL (10 * 60 * HZ)

static void rehash_flow_table(struct work_struct *work);

static DECLARE_DELAYED_WORK(rehash_flow_wq, rehash_flow_table);



int ovs_net_id __read_mostly;
@@ -1289,22 +1287,25 @@ static int ovs_flow_cmd_new_or_set(struct sk_buff *skb, struct genl_info *info) 
	/* Check if this is a duplicate flow */

	flow = ovs_flow_lookup(table, &key);

	if (!flow) {

		struct flow_table *new_table = NULL;

		struct sw_flow_mask *mask_p;



		/* Bail out if we're not allowed to create a new flow. */

		error = -ENOENT;

		if (info->genlhdr->cmd == OVS_FLOW_CMD_SET)

			goto err_unlock_ovs;



		/* Expand table, if necessary, to make room. */

		if (ovs_flow_tbl_need_to_expand(table)) {

			struct flow_table *new_table;



		if (ovs_flow_tbl_need_to_expand(table))

			new_table = ovs_flow_tbl_expand(table);

			if (!IS_ERR(new_table)) {

		else if (time_after(jiffies, dp->last_rehash + REHASH_FLOW_INTERVAL))

			new_table = ovs_flow_tbl_rehash(table);



		if (new_table && !IS_ERR(new_table)) {

			rcu_assign_pointer(dp->table, new_table);

			ovs_flow_tbl_destroy(table, true);

			table = ovsl_dereference(dp->table);

			}

			dp->last_rehash = jiffies;

		}



		/* Allocate flow. */
@@ -2336,32 +2337,6 @@ static int dp_register_genl(void) 
	return err;

}



static void rehash_flow_table(struct work_struct *work)

{

	struct datapath *dp;

	struct net *net;



	ovs_lock();

	rtnl_lock();

	for_each_net(net) {

		struct ovs_net *ovs_net = net_generic(net, ovs_net_id);



		list_for_each_entry(dp, &ovs_net->dps, list_node) {

			struct flow_table *old_table = ovsl_dereference(dp->table);

			struct flow_table *new_table;



			new_table = ovs_flow_tbl_rehash(old_table);

			if (!IS_ERR(new_table)) {

				rcu_assign_pointer(dp->table, new_table);

				ovs_flow_tbl_destroy(old_table, true);

			}

		}

	}

	rtnl_unlock();

	ovs_unlock();

	schedule_delayed_work(&rehash_flow_wq, REHASH_FLOW_INTERVAL);

}



static int __net_init ovs_init_net(struct net *net)

{

	struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
@@ -2419,8 +2394,6 @@ static int __init dp_init(void) 
	if (err < 0)

		goto error_unreg_notifier;



	schedule_delayed_work(&rehash_flow_wq, REHASH_FLOW_INTERVAL);



	return 0;



error_unreg_notifier:
@@ -2437,7 +2410,6 @@ static int __init dp_init(void) 


static void dp_cleanup(void)

{

	cancel_delayed_work_sync(&rehash_flow_wq);

	dp_unregister_genl(ARRAY_SIZE(dp_genl_families));

	unregister_netdevice_notifier(&ovs_dp_device_notifier);

	unregister_pernet_device(&ovs_net_ops);

net/openvswitch/datapath.h

+2 −0
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct dp_stats_percpu { 
 * ovs_mutex and RCU.

 * @stats_percpu: Per-CPU datapath statistics.

 * @net: Reference to net namespace.

 * @last_rehash: Timestamp of last rehash.

 *

 * Context: See the comment on locking at the top of datapath.c for additional

 * locking information.
@@ -83,6 +84,7 @@ struct datapath { 
	/* Network namespace ref. */

	struct net *net;

#endif

	unsigned long last_rehash;

};



/**