[ovs-dev] [PATCH] datapath: Optimize recirc action.

Pravin Shelar pshelar at nicira.com
Thu Aug 7 21:59:12 UTC 2014


On Thu, Aug 7, 2014 at 2:01 PM, Andy Zhou <azhou at nicira.com> wrote:
> On Thu, Aug 7, 2014 at 12:32 PM, Pravin B Shelar <pshelar at nicira.com> wrote:
>> OVS need to flow key for flow lookup in recic action. OVS
>> does key extract in recic action. Most of cases we could
>> use OVS_CB packet key directly and can avoid packet flow key
>> extract. SET action we can update flow-key along with packet
>> to keep it consistent. But there are some action like MPLS
>> pop which forces OVS to do flow-extract. In such cases we
>> can mark flow key as invalid so that subsequent recirc
>> action can do full flow extract.
>
> Does this optimization apply to sample action as well?
>
Good catch. sample action needs its own packet key.

>>
>> Signed-off-by: Pravin B Shelar <pshelar at nicira.com>
>> ---
>>  datapath/actions.c | 197 +++++++++++++++++++++++++++++++++++++++++++----------
>>  1 file changed, 160 insertions(+), 37 deletions(-)
>>
>> diff --git a/datapath/actions.c b/datapath/actions.c
>> index efc64f1..3c004a8 100644
>> --- a/datapath/actions.c
>> +++ b/datapath/actions.c
>> @@ -40,6 +40,90 @@
>>  #include "vlan.h"
>>  #include "vport.h"
>>
>> +static void flow_key_set_priority(struct sk_buff *skb, u32 priority)
>
> Why not just pass in pkt_key, instead of skb?
I want to hide OVS_CB(skb)->pkt_key inside these functions. I think it
improves readability.

>
>> +{
>> +       OVS_CB(skb)->pkt_key->phy.priority = priority;
>> +}
>> +
>> +static void flow_key_set_skb_mark(struct sk_buff *skb, u32 skb_mark)
>> +{
>> +       OVS_CB(skb)->pkt_key->phy.skb_mark = skb_mark;
>> +}
>> +
>> +static void flow_key_set_eth_src(struct sk_buff *skb, const u8 addr[])
>> +{
>> +       ether_addr_copy(OVS_CB(skb)->pkt_key->eth.src, addr);
>> +}
>> +
>> +static void flow_key_set_eth_dst(struct sk_buff *skb, const u8 addr[])
>> +{
>> +       ether_addr_copy(OVS_CB(skb)->pkt_key->eth.dst, addr);
>> +}
>> +
>> +static void flow_key_set_vlan_tci(struct sk_buff *skb, __be16 tci)
>> +{
>> +       OVS_CB(skb)->pkt_key->eth.tci = tci;
>> +}
>> +
>> +static void flow_key_set_ipv4_src(struct sk_buff *skb, __be32 addr)
>> +{
>> +       OVS_CB(skb)->pkt_key->ipv4.addr.src = addr;
>> +}
>> +
>> +static void flow_key_set_ipv4_dst(struct sk_buff *skb, __be32 addr)
>> +{
>> +       OVS_CB(skb)->pkt_key->ipv4.addr.src = addr;
>> +}
>> +
>> +static void flow_key_set_ipv4_tos(struct sk_buff *skb, const struct iphdr *nh)
>> +{
>> +       OVS_CB(skb)->pkt_key->ip.tos = nh->tos;
>> +}
>> +
>> +static void flow_key_set_ip_ttl(struct sk_buff *skb, u8 ttl)
>> +{
>> +       OVS_CB(skb)->pkt_key->ip.ttl = ttl;
>> +}
>> +
>> +static void flow_key_set_ipv6_src(struct sk_buff *skb,
>> +                                 const __be32 addr[4])
>> +{
>> +       memcpy(&OVS_CB(skb)->pkt_key->ipv6.addr.src, addr, sizeof(__be32[4]));
>> +}
>> +
>> +static void flow_key_set_ipv6_dst(struct sk_buff *skb,
>> +                                 const __be32 addr[4])
>> +{
>> +       memcpy(&OVS_CB(skb)->pkt_key->ipv6.addr.dst, addr, sizeof(__be32[4]));
>> +}
>> +
>> +static void flow_key_set_ipv6_fl(struct sk_buff *skb,
>> +                                const struct ipv6hdr *nh)
>> +{
>> +       OVS_CB(skb)->pkt_key->ipv6.label = *(__be32 *)nh &
>> +                                          htonl(IPV6_FLOWINFO_FLOWLABEL);
>> +}
>> +
>> +static void flow_key_set_tp_src(struct sk_buff *skb, __be16 port)
>> +{
>> +       OVS_CB(skb)->pkt_key->tp.src = port;
>> +}
>> +
>> +static void flow_key_set_tp_dst(struct sk_buff *skb, __be16 port)
>> +{
>> +       OVS_CB(skb)->pkt_key->tp.dst = port;
>> +}
>> +
>> +static void invalidate_skb_flow_key(struct sk_buff *skb)
>> +{
>> +       OVS_CB(skb)->pkt_key->eth.type = 0;
>> +}
>> +
>> +static bool is_skb_flow_key_valid(struct sk_buff *skb)
>> +{
>> +       return !!OVS_CB(skb)->pkt_key->eth.type;
>> +}
>> +
>>  static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
>>                               const struct nlattr *attr, int len);
>>
>> @@ -90,6 +174,7 @@ static int push_mpls(struct sk_buff *skb,
>>         if (!ovs_skb_get_inner_protocol(skb))
>>                 ovs_skb_set_inner_protocol(skb, skb->protocol);
>>         skb->protocol = mpls->mpls_ethertype;
>> +       invalidate_skb_flow_key(skb);
>>         return 0;
>>  }
>>
>> @@ -120,6 +205,7 @@ static int pop_mpls(struct sk_buff *skb, const __be16 ethertype)
>>         hdr->h_proto = ethertype;
>>         if (eth_p_mpls(skb->protocol))
>>                 skb->protocol = ethertype;
>> +       invalidate_skb_flow_key(skb);
>>         return 0;
>>  }
>>
>> @@ -139,7 +225,7 @@ static int set_mpls(struct sk_buff *skb, const __be32 *mpls_lse)
>>         }
>>
>>         *stack = *mpls_lse;
>> -
>> +       invalidate_skb_flow_key(skb);
>>         return 0;
>>  }
>>
>> @@ -189,9 +275,12 @@ static int pop_vlan(struct sk_buff *skb)
>>         }
>>         /* move next vlan tag to hw accel tag */
>>         if (likely(skb->protocol != htons(ETH_P_8021Q) ||
>> -                  skb->len < VLAN_ETH_HLEN))
>> +                  skb->len < VLAN_ETH_HLEN)) {
>> +               flow_key_set_vlan_tci(skb, 0);
>>                 return 0;
>> +       }
>>
>> +       invalidate_skb_flow_key(skb);
>>         err = __pop_vlan_tci(skb, &tci);
>>         if (unlikely(err))
>>                 return err;
>> @@ -220,6 +309,7 @@ static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vla
>>
>>         }
>>         __vlan_hwaccel_put_tag(skb, vlan->vlan_tpid, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT);
>> +       invalidate_skb_flow_key(skb);
>>         return 0;
>>  }
>>
>> @@ -238,11 +328,13 @@ static int set_eth_addr(struct sk_buff *skb,
>>
>>         ovs_skb_postpush_rcsum(skb, eth_hdr(skb), ETH_ALEN * 2);
>>
>> +       flow_key_set_eth_src(skb, eth_key->eth_src);
>> +       flow_key_set_eth_dst(skb, eth_key->eth_dst);
>>         return 0;
>>  }
>>
>>  static void set_ip_addr(struct sk_buff *skb, struct iphdr *nh,
>> -                               __be32 *addr, __be32 new_addr)
>> +                       __be32 *addr, __be32 new_addr)
>>  {
>>         int transport_len = skb->len - skb_transport_offset(skb);
>>
>> @@ -333,17 +425,25 @@ static int set_ipv4(struct sk_buff *skb, const struct ovs_key_ipv4 *ipv4_key)
>>
>>         nh = ip_hdr(skb);
>>
>> -       if (ipv4_key->ipv4_src != nh->saddr)
>> +       if (ipv4_key->ipv4_src != nh->saddr) {
>>                 set_ip_addr(skb, nh, &nh->saddr, ipv4_key->ipv4_src);
>> +               flow_key_set_ipv4_src(skb, ipv4_key->ipv4_src);
>> +       }
>>
>> -       if (ipv4_key->ipv4_dst != nh->daddr)
>> +       if (ipv4_key->ipv4_dst != nh->daddr) {
>>                 set_ip_addr(skb, nh, &nh->daddr, ipv4_key->ipv4_dst);
>> +               flow_key_set_ipv4_dst(skb, ipv4_key->ipv4_dst);
>> +       }
>>
>> -       if (ipv4_key->ipv4_ != nh->tos)
>> +       if (ipv4_key->ipv4_tos != nh->tos) {
>>                 ipv4_change_dsfield(nh, 0, ipv4_key->ipv4_tos);
>> +               flow_key_set_ipv4_tos(skb, nh);
>
> why not pass ipv4_key->ipv4_tos instead of nh?
>
ok. I will do it.

>> +       }
>>
>> -       if (ipv4_key->ipv4_ttl != nh->ttl)
>> +       if (ipv4_key->ipv4_ttl != nh->ttl) {
>>                 set_ip_ttl(skb, nh, ipv4_key->ipv4_ttl);
>> +               flow_key_set_ip_ttl(skb, ipv4_key->ipv4_ttl);
>> +       }
>>
>>         return 0;
>>  }
>> @@ -364,9 +464,11 @@ static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
>>         saddr = (__be32 *)&nh->saddr;
>>         daddr = (__be32 *)&nh->daddr;
>>
>> -       if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src)))
>> +       if (memcmp(ipv6_key->ipv6_src, saddr, sizeof(ipv6_key->ipv6_src))) {
>>                 set_ipv6_addr(skb, ipv6_key->ipv6_proto, saddr,
>>                               ipv6_key->ipv6_src, true);
>> +               flow_key_set_ipv6_src(skb, ipv6_key->ipv6_src);
>> +       }
>>
>>         if (memcmp(ipv6_key->ipv6_dst, daddr, sizeof(ipv6_key->ipv6_dst))) {
>>                 unsigned int offset = 0;
>> @@ -380,12 +482,15 @@ static int set_ipv6(struct sk_buff *skb, const struct ovs_key_ipv6 *ipv6_key)
>>
>>                 set_ipv6_addr(skb, ipv6_key->ipv6_proto, daddr,
>>                               ipv6_key->ipv6_dst, recalc_csum);
>> +               flow_key_set_ipv6_dst(skb, ipv6_key->ipv6_dst);
>>         }
>>
>>         set_ipv6_tc(nh, ipv6_key->ipv6_tclass);
>>         set_ipv6_fl(nh, ntohl(ipv6_key->ipv6_label));
>> -       nh->hop_limit = ipv6_key->ipv6_hlimit;
>> +       flow_key_set_ipv6_fl(skb, nh);
>>
>> +       nh->hop_limit = ipv6_key->ipv6_hlimit;
>> +       flow_key_set_ip_ttl(skb, ipv6_key->ipv6_hlimit);
>>         return 0;
>>  }
>>
>> @@ -424,11 +529,15 @@ static int set_udp(struct sk_buff *skb, const struct ovs_key_udp *udp_port_key)
>>                 return err;
>>
>>         uh = udp_hdr(skb);
>> -       if (udp_port_key->udp_src != uh->source)
>> +       if (udp_port_key->udp_src != uh->source) {
>>                 set_udp_port(skb, &uh->source, udp_port_key->udp_src);
>> +               flow_key_set_tp_src(skb, udp_port_key->udp_src);
>> +       }
>>
>> -       if (udp_port_key->udp_dst != uh->dest)
>> +       if (udp_port_key->udp_dst != uh->dest) {
>>                 set_udp_port(skb, &uh->dest, udp_port_key->udp_dst);
>> +               flow_key_set_tp_dst(skb, udp_port_key->udp_dst);
>> +       }
>>
>>         return 0;
>>  }
>> @@ -444,17 +553,21 @@ static int set_tcp(struct sk_buff *skb, const struct ovs_key_tcp *tcp_port_key)
>>                 return err;
>>
>>         th = tcp_hdr(skb);
>> -       if (tcp_port_key->tcp_src != th->source)
>> +       if (tcp_port_key->tcp_src != th->source) {
>>                 set_tp_port(skb, &th->source, tcp_port_key->tcp_src, &th->check);
>> +               flow_key_set_tp_src(skb, tcp_port_key->tcp_src);
>> +       }
>>
>> -       if (tcp_port_key->tcp_dst != th->dest)
>> +       if (tcp_port_key->tcp_dst != th->dest) {
>>                 set_tp_port(skb, &th->dest, tcp_port_key->tcp_dst, &th->check);
>> +               flow_key_set_tp_dst(skb, tcp_port_key->tcp_dst);
>> +       }
>>
>>         return 0;
>>  }
>>
>>  static int set_sctp(struct sk_buff *skb,
>> -                    const struct ovs_key_sctp *sctp_port_key)
>> +                   const struct ovs_key_sctp *sctp_port_key)
>>  {
>>         struct sctphdr *sh;
>>         int err;
>> @@ -481,6 +594,8 @@ static int set_sctp(struct sk_buff *skb,
>>                 sh->checksum = old_csum ^ old_correct_csum ^ new_csum;
>>
>>                 skb_clear_hash(skb);
>> +               flow_key_set_tp_src(skb, sctp_port_key->sctp_src);
>> +               flow_key_set_tp_dst(skb, sctp_port_key->sctp_dst);
>>         }
>>
>>         return 0;
>> @@ -603,10 +718,12 @@ static int execute_set_action(struct sk_buff *skb,
>>         switch (nla_type(nested_attr)) {
>>         case OVS_KEY_ATTR_PRIORITY:
>>                 skb->priority = nla_get_u32(nested_attr);
>> +               flow_key_set_priority(skb, skb->priority);
>>                 break;
>>
>>         case OVS_KEY_ATTR_SKB_MARK:
>>                 skb->mark = nla_get_u32(nested_attr);
>> +               flow_key_set_skb_mark(skb, skb->mark);
>>                 break;
>>
>>         case OVS_KEY_ATTR_TUNNEL_INFO:
>> @@ -646,20 +763,40 @@ static int execute_set_action(struct sk_buff *skb,
>>  }
>>
>>  static int execute_recirc(struct datapath *dp, struct sk_buff *skb,
>> -                         const struct nlattr *a)
>> +                         const struct nlattr *a, int rem)
>>  {
>>         struct sw_flow_key recirc_key;
>>         int err;
>>
>> -       err = ovs_flow_key_extract_recirc(nla_get_u32(a), OVS_CB(skb)->pkt_key,
>> -                                         skb, &recirc_key);
>> -       if (err) {
>> -               kfree_skb(skb);
>> -               return err;
>> +       if (!last_action(a, rem)) {
>> +               /* Recirc action is the not the last action
>> +                * of the action list. */
>> +               skb = skb_clone(skb, GFP_ATOMIC);
>> +
>> +               /* Skip the recirc action when out of memory, but
>> +                * continue on with the rest of the action list. */
>> +               if (!skb)
>> +                       return 0;
>>         }
>>
>> -       ovs_dp_process_packet(skb, true);
>> +       if (is_skb_flow_key_valid(skb)) {
>> +               if (!last_action(a, rem)) {
>> +                       recirc_key = *OVS_CB(skb)->pkt_key;
>> +                       OVS_CB(skb)->pkt_key = &recirc_key;
>> +               }
>> +               OVS_CB(skb)->pkt_key->recirc_id = nla_get_u32(a);
>
> How about adding two new static inline functions:
>   * flow_key_clone_recirc(nla_get_n32(a), skb, &recirc_key);
>   * flow_key_set_recirc_id(skb, nla_get_n32(a));
>
> The above logic will become even easier to understand and more consistent with
> the API usage in this function. It should also help with the follow on
> non-recursive changes.
>
ok.


>> +       } else {
>> +               struct sw_flow_key *pkt_key = OVS_CB(skb)->pkt_key;
>>
>> +               err = ovs_flow_key_extract_recirc(nla_get_u32(a), pkt_key,
>> +                                                 skb, &recirc_key);
>> +               if (err) {
>> +                       kfree_skb(skb);
>> +                       return err;
>> +               }
>> +       }
>> +
>> +       ovs_dp_process_packet(skb, true);
>>         return 0;
>>  }
>>
>> @@ -719,23 +856,9 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
>>                         err = pop_vlan(skb);
>>                         break;
>>
>> -               case OVS_ACTION_ATTR_RECIRC: {
>> -                       struct sk_buff *recirc_skb;
>> -
>> -                       if (last_action(a, rem))
>> -                               return execute_recirc(dp, skb, a);
>> -
>> -                       /* Recirc action is the not the last action
>> -                        * of the action list. */
>> -                       recirc_skb = skb_clone(skb, GFP_ATOMIC);
>> -
>> -                       /* Skip the recirc action when out of memory, but
>> -                        * continue on with the rest of the action list. */
>> -                       if (recirc_skb)
>> -                               err = execute_recirc(dp, recirc_skb, a);
>> -
>> +               case OVS_ACTION_ATTR_RECIRC:
>> +                       err = execute_recirc(dp, skb, a, rem);
>>                         break;
>> -               }
>>
>>                 case OVS_ACTION_ATTR_SET:
>>                         err = execute_set_action(skb, nla_data(a));
>> --
>> 1.9.3
>>
>> _______________________________________________
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