Message ID | 50210C23.2070203@parallels.com |
---|---|
State | Changes Requested, archived |
Delegated to: | David Miller |
Headers | show |
On Tue, 2012-08-07 at 16:37 +0400, Pavel Emelyanov wrote: > >> @@ -62,6 +62,7 @@ struct net { > >> struct sock *rtnl; /* rtnetlink socket */ > >> struct sock *genl_sock; > >> > >> + int ifindex; > > > > could you place ifindex right after dev_base_seq : avoid two holes > > and use the same cache line, dirtied in > > list_netdevice()/unlist_netdevice() > > Sure! Here it is: > > From: Pavel Emelyanov <xemul@parallels.com> > Subject: [PATCH 4/5] net: Make ifindex generation per-net namespace > > Strictly speaking this is only _really_ required for checkpoint-restore to > make loopback device always have the same index. > > This change appears to be safe wrt "ifindex should be unique per-system" > concept, as all the ifindex usage is either already made per net namespace > of is explicitly limited with init_net only. > > There are two cool side effects of this. The first one -- ifindices of > devices in container are always small, regardless of how many containers > we've started (and re-started) so far. The second one is -- we can speed > up the loopback ifidex access as shown in the next patch. > > v2: Place ifindex right after dev_base_seq : avoid two holes and use the > same cache line, dirtied in list_netdevice()/unlist_netdevice() > > Signed-off-by: Pavel Emelyanov <xemul@parallels.com> > --- Acked-by: Eric Dumazet <edumazet@google.com> -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index ae1cd6c..6dc3db3 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -66,6 +66,7 @@ struct net { struct hlist_head *dev_name_head; struct hlist_head *dev_index_head; unsigned int dev_base_seq; /* protected by rtnl_mutex */ + int ifindex; /* core fib_rules */ struct list_head rules_ops; diff --git a/net/core/dev.c b/net/core/dev.c index 3ca300d..1f06df8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5221,12 +5221,12 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg) */ static int dev_new_index(struct net *net) { - static int ifindex; + int ifindex = net->ifindex; for (;;) { if (++ifindex <= 0) ifindex = 1; if (!__dev_get_by_index(net, ifindex)) - return ifindex; + return net->ifindex = ifindex; } }