Merge branch 'net-avoid-slow-rcu'

Eric Dumazet says: ==================== net: avoid slow rcu synchronizations in cleanup_net() RTNL is a contended mutex, we prefer to expedite rcu synchronizations in contexts we hold RTNL. Similarly, cleanup_net() is a single threaded critical component and should also use synchronize_rcu_expedited() even when not holding RTNL. First patch removes a barrier with no clear purpose in ipv6_mc_down() ==================== Signed-off-by: David S. Miller <[email protected]>
cxl-micron-reskit · Feb 12, 2024 · 0f37666 · 0f37666
2 parents 03f568a + 1ebb85f
commit 0f37666
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Showing 6 changed files with 6 additions and 7 deletions.
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
@@ -841,7 +841,7 @@ void br_vlan_flush(struct net_bridge *br)
 	vg = br_vlan_group(br);
 	__vlan_flush(br, NULL, vg);
 	RCU_INIT_POINTER(br->vlgrp, NULL);
-	synchronize_rcu();
+	synchronize_net();
 	__vlan_group_free(vg);
 }
 
@@ -1372,7 +1372,7 @@ void nbp_vlan_flush(struct net_bridge_port *port)
 	vg = nbp_vlan_group(port);
 	__vlan_flush(port->br, port, vg);
 	RCU_INIT_POINTER(port->vlgrp, NULL);
-	synchronize_rcu();
+	synchronize_net();
 	__vlan_group_free(vg);
 }
 

diff --git a/net/core/dev.c b/net/core/dev.c
@@ -1239,7 +1239,7 @@ int dev_change_name(struct net_device *dev, const char *newname)
 	netdev_name_node_del(dev->name_node);
 	write_unlock(&dev_base_lock);
 
-	synchronize_rcu();
+	synchronize_net();
 
 	write_lock(&dev_base_lock);
 	netdev_name_node_add(net, dev->name_node);

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
@@ -622,7 +622,7 @@ static void cleanup_net(struct work_struct *work)
 	 * the rcu_barrier() below isn't sufficient alone.
 	 * Also the pre_exit() and exit() methods need this barrier.
 	 */
-	synchronize_rcu();
+	synchronize_rcu_expedited();
 
 	rtnl_lock();
 	list_for_each_entry_reverse(ops, &pernet_list, list) {

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
@@ -501,7 +501,7 @@ static void tnode_free(struct key_vector *tn)
 
 	if (tnode_free_size >= READ_ONCE(sysctl_fib_sync_mem)) {
 		tnode_free_size = 0;
-		synchronize_rcu();
+		synchronize_net();
 	}
 }
 

diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
@@ -2719,7 +2719,6 @@ void ipv6_mc_down(struct inet6_dev *idev)
 	/* Should stop work after group drop. or we will
 	 * start work again in mld_ifc_event()
 	 */
-	synchronize_net();
 	mld_query_stop_work(idev);
 	mld_report_stop_work(idev);
 

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
@@ -2530,7 +2530,7 @@ void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
 	 *  netfilter framework.  Roll on, two-stage module
 	 *  delete...
 	 */
-	synchronize_net();
+	synchronize_rcu_expedited();
 i_see_dead_people:
 	busy = 0;
 	list_for_each_entry(net, net_exit_list, exit_list) {