[PATCH RFC net-next 4/4] bridge: add ability to turn off fdb used updates
From: Nikolay Aleksandrov <hidden>
Date: 2017-01-31 15:32:31
Subsystem:
ethernet bridge, networking drivers, networking [general], the rest · Maintainers:
Nikolay Aleksandrov, Ido Schimmel, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Being able to turn off fdb "used" updates makes it possible to avoid false-sharing on each packet transmit/receive for that fdb. The best way to completely avoid false-sharing is by binding ports to CPUs so receive will write to the "updated" field only on a single CPU and transmit to that fdb will not touch the "used" field. The default is used_enabled = 1 to avoid breaking user-space, strongly suggest if not needed to set it to 0. Signed-off-by: Nikolay Aleksandrov <redacted> --- include/uapi/linux/if_link.h | 1 + net/bridge/br_device.c | 1 + net/bridge/br_input.c | 3 ++- net/bridge/br_netlink.c | 10 +++++++++- net/bridge/br_private.h | 1 + net/bridge/br_sysfs_br.c | 23 +++++++++++++++++++++++ 6 files changed, 37 insertions(+), 2 deletions(-)
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index b9aa5641ebe5..8bcd234fed03 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h@@ -277,6 +277,7 @@ enum { IFLA_BR_MCAST_STATS_ENABLED, IFLA_BR_MCAST_IGMP_VERSION, IFLA_BR_MCAST_MLD_VERSION, + IFLA_BR_USED_ENABLED, __IFLA_BR_MAX, };
diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index 89b414fd1901..b1fa1b031fea 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c@@ -408,6 +408,7 @@ void br_dev_setup(struct net_device *dev) br->bridge_hello_time = br->hello_time = 2 * HZ; br->bridge_forward_delay = br->forward_delay = 15 * HZ; br->bridge_ageing_time = br->ageing_time = BR_DEFAULT_AGEING_TIME; + br->used_enabled = 1; dev->max_mtu = ETH_MAX_MTU; br_netfilter_rtable_init(br);
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 855b72fbe1da..8a320901aaa7 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c@@ -197,7 +197,8 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb if (dst->is_local) return br_pass_frame_up(skb); - dst->used = jiffies; + if (br->used_enabled) + dst->used = jiffies; br_forward(dst->dst, skb, local_rcv, false); } else { if (!mcast_hit)
diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c
index d63ad8337dcd..49272efaad00 100644
--- a/net/bridge/br_netlink.c
+++ b/net/bridge/br_netlink.c@@ -851,6 +851,7 @@ static const struct nla_policy br_policy[IFLA_BR_MAX + 1] = { [IFLA_BR_MCAST_STATS_ENABLED] = { .type = NLA_U8 }, [IFLA_BR_MCAST_IGMP_VERSION] = { .type = NLA_U8 }, [IFLA_BR_MCAST_MLD_VERSION] = { .type = NLA_U8 }, + [IFLA_BR_USED_ENABLED] = { .type = NLA_U8 }, }; static int br_changelink(struct net_device *brdev, struct nlattr *tb[],
@@ -1102,6 +1103,11 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[], br->nf_call_arptables = val ? true : false; } #endif + if (data[IFLA_BR_USED_ENABLED]) { + u8 val = nla_get_u8(data[IFLA_BR_USED_ENABLED]); + + br->used_enabled = !!val; + } return 0; }
@@ -1175,6 +1181,7 @@ static size_t br_get_size(const struct net_device *brdev) nla_total_size(sizeof(u8)) + /* IFLA_BR_NF_CALL_IP6TABLES */ nla_total_size(sizeof(u8)) + /* IFLA_BR_NF_CALL_ARPTABLES */ #endif + nla_total_size(sizeof(u8)) + /* IFLA_BR_USED_ENABLED */ 0; }
@@ -1246,7 +1253,8 @@ static int br_fill_info(struct sk_buff *skb, const struct net_device *brdev) nla_put_u32(skb, IFLA_BR_MCAST_STARTUP_QUERY_CNT, br->multicast_startup_query_count) || nla_put_u8(skb, IFLA_BR_MCAST_IGMP_VERSION, - br->multicast_igmp_version)) + br->multicast_igmp_version) || + nla_put_u8(skb, IFLA_BR_USED_ENABLED, br->used_enabled)) return -EMSGSIZE; #if IS_ENABLED(CONFIG_IPV6) if (nla_put_u8(skb, IFLA_BR_MCAST_MLD_VERSION,
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 1e1b9a07e2da..4b6eb2393d7e 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h@@ -281,6 +281,7 @@ struct net_bridge { struct net_device *dev; struct pcpu_sw_netstats __percpu *stats; /* These fields are accessed on each packet */ + u8 used_enabled; #ifdef CONFIG_BRIDGE_VLAN_FILTERING u8 vlan_enabled; u8 vlan_stats_enabled;
diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 0f4034934d56..22adc29e8721 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c@@ -334,6 +334,28 @@ static ssize_t flush_store(struct device *d, } static DEVICE_ATTR_WO(flush); +static ssize_t used_enabled_show(struct device *d, + struct device_attribute *attr, char *buf) +{ + struct net_bridge *br = to_bridge(d); + + return sprintf(buf, "%u\n", br->used_enabled); +} + +static int set_used_enabled(struct net_bridge *br, unsigned long val) +{ + br->used_enabled = !!val; + return 0; +} + +static ssize_t used_enabled_store(struct device *d, + struct device_attribute *attr, + const char *buf, size_t len) +{ + return store_bridge_parm(d, buf, len, set_used_enabled); +} +static DEVICE_ATTR_RW(used_enabled); + #ifdef CONFIG_BRIDGE_IGMP_SNOOPING static ssize_t multicast_router_show(struct device *d, struct device_attribute *attr, char *buf)
@@ -829,6 +851,7 @@ static struct attribute *bridge_attrs[] = { &dev_attr_gc_timer.attr, &dev_attr_group_addr.attr, &dev_attr_flush.attr, + &dev_attr_used_enabled.attr, #ifdef CONFIG_BRIDGE_IGMP_SNOOPING &dev_attr_multicast_router.attr, &dev_attr_multicast_snooping.attr,
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2.1.4