From 1139e241ec436b9e9610c7a33ac5c6657f87fda1 Mon Sep 17 00:00:00 2001 From: Jarno Rajahalme Date: Mon, 5 May 2014 09:54:49 -0700 Subject: openvswitch: Compact sw_flow_key. Minimize padding in sw_flow_key and move 'tp' top the main struct. These changes simplify code when accessing the transport port numbers and the tcp flags, and makes the sw_flow_key 8 bytes smaller on 64-bit systems (128->120 bytes). These changes also make the keys for IPv4 packets to fit in one cache line. There is a valid concern for safety of packing the struct ovs_key_ipv4_tunnel, as it would be possible to take the address of the tun_id member as a __be64 * which could result in unaligned access in some systems. However: - sw_flow_key itself is 64-bit aligned, so the tun_id within is always 64-bit aligned. - We never make arrays of ovs_key_ipv4_tunnel (which would force every second tun_key to be misaligned). - We never take the address of the tun_id in to a __be64 *. - Whereever we use struct ovs_key_ipv4_tunnel outside the sw_flow_key, it is in stack (on tunnel input functions), where compiler has full control of the alignment. Signed-off-by: Jarno Rajahalme Signed-off-by: Pravin B Shelar --- net/openvswitch/flow.h | 29 +++++++++++------------------ 1 file changed, 11 insertions(+), 18 deletions(-) (limited to 'net/openvswitch/flow.h') diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h index ddcebc53224f..a292bf8ad75c 100644 --- a/net/openvswitch/flow.h +++ b/net/openvswitch/flow.h @@ -47,7 +47,7 @@ struct ovs_key_ipv4_tunnel { __be16 tun_flags; u8 ipv4_tos; u8 ipv4_ttl; -}; +} __packed __aligned(4); /* Minimize padding. */ static inline void ovs_flow_tun_key_init(struct ovs_key_ipv4_tunnel *tun_key, const struct iphdr *iph, __be64 tun_id, @@ -71,7 +71,7 @@ struct sw_flow_key { u32 priority; /* Packet QoS priority. */ u32 skb_mark; /* SKB mark. */ u16 in_port; /* Input switch port (or DP_MAX_PORTS). */ - } phy; + } __packed phy; /* Safe when right after 'tun_key'. */ struct { u8 src[ETH_ALEN]; /* Ethernet source address. */ u8 dst[ETH_ALEN]; /* Ethernet destination address. */ @@ -84,23 +84,21 @@ struct sw_flow_key { u8 ttl; /* IP TTL/hop limit. */ u8 frag; /* One of OVS_FRAG_TYPE_*. */ } ip; + struct { + __be16 src; /* TCP/UDP/SCTP source port. */ + __be16 dst; /* TCP/UDP/SCTP destination port. */ + __be16 flags; /* TCP flags. */ + } tp; union { struct { struct { __be32 src; /* IP source address. */ __be32 dst; /* IP destination address. */ } addr; - union { - struct { - __be16 src; /* TCP/UDP/SCTP source port. */ - __be16 dst; /* TCP/UDP/SCTP destination port. */ - __be16 flags; /* TCP flags. */ - } tp; - struct { - u8 sha[ETH_ALEN]; /* ARP source hardware address. */ - u8 tha[ETH_ALEN]; /* ARP target hardware address. */ - } arp; - }; + struct { + u8 sha[ETH_ALEN]; /* ARP source hardware address. */ + u8 tha[ETH_ALEN]; /* ARP target hardware address. */ + } arp; } ipv4; struct { struct { @@ -108,11 +106,6 @@ struct sw_flow_key { struct in6_addr dst; /* IPv6 destination address. */ } addr; __be32 label; /* IPv6 flow label. */ - struct { - __be16 src; /* TCP/UDP/SCTP source port. */ - __be16 dst; /* TCP/UDP/SCTP destination port. */ - __be16 flags; /* TCP flags. */ - } tp; struct { struct in6_addr target; /* ND target address. */ u8 sll[ETH_ALEN]; /* ND source link layer address. */ -- cgit