On 2/23/23 12:27, Chris Mi wrote:
> In thread handler 0, add netdev offload recv in normal recv upcalls.
> To avoid starvation, introduce a flag to alternate the order of
> receiving normal upcalls and offload upcalls based on that flag.
> 
> Add similar change for recv_wait.
> 
> Signed-off-by: Chris Mi <[email protected]>
> Reviewed-by: Roi Dayan <[email protected]>
> ---
>  lib/dpif-netlink.c            | 46 ++++++++++++++++++++++++++++++++---
>  ofproto/ofproto-dpif-upcall.c | 23 +++++++++++++++---
>  2 files changed, 62 insertions(+), 7 deletions(-)
> 
> diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
> index 586fb8893..9f67db1be 100644
> --- a/lib/dpif-netlink.c
> +++ b/lib/dpif-netlink.c
> @@ -201,6 +201,12 @@ struct dpif_handler {
>      struct nl_sock *sock;         /* Each handler thread holds one netlink
>                                       socket. */
>  
> +    /* Thread handler 0 deals with both netdev offload recv and normal
> +     * recv upcalls. To avoid starvation, introduce a flag to alternate
> +     * the order.
> +     */
> +    bool recv_offload_first;
> +
>  #ifdef _WIN32
>      /* Pool of sockets. */
>      struct dpif_windows_vport_sock *vport_sock_pool;
> @@ -3130,13 +3136,12 @@ dpif_netlink_recv_vport_dispatch(struct dpif_netlink 
> *dpif,
>  #endif
>  
>  static int
> -dpif_netlink_recv(struct dpif *dpif_, uint32_t handler_id,
> -                  struct dpif_upcall *upcall, struct ofpbuf *buf)
> +dpif_netlink_recv__(struct dpif *dpif_, uint32_t handler_id,
> +                    struct dpif_upcall *upcall, struct ofpbuf *buf)
>  {
>      struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
>      int error;
>  
> -    fat_rwlock_rdlock(&dpif->upcall_lock);
>  #ifdef _WIN32
>      error = dpif_netlink_recv_windows(dpif, handler_id, upcall, buf);
>  #else
> @@ -3147,6 +3152,38 @@ dpif_netlink_recv(struct dpif *dpif_, uint32_t 
> handler_id,
>                                                   handler_id, upcall, buf);
>      }
>  #endif
> +
> +    return error;
> +}
> +
> +static int
> +dpif_netlink_recv(struct dpif *dpif_, uint32_t handler_id,
> +                  struct dpif_upcall *upcall, struct ofpbuf *buf)
> +{
> +    struct dpif_netlink *dpif = dpif_netlink_cast(dpif_);
> +    struct dpif_handler *handler;
> +    int error;
> +
> +    fat_rwlock_rdlock(&dpif->upcall_lock);
> +    if (handler_id) {
> +        error = dpif_netlink_recv__(dpif_, handler_id, upcall, buf);
> +        fat_rwlock_unlock(&dpif->upcall_lock);
> +        return error;
> +    }
> +
> +    handler = &dpif->handlers[handler_id];
> +    if (handler->recv_offload_first) {
> +        error = netdev_offload_recv(upcall, buf);
> +        if (error == EAGAIN) {
> +            error = dpif_netlink_recv__(dpif_, handler_id, upcall, buf);
> +        }
> +    } else {
> +        error = dpif_netlink_recv__(dpif_, handler_id, upcall, buf);
> +        if (error == EAGAIN) {
> +            error = netdev_offload_recv(upcall, buf);
> +        }
> +    }
> +    handler->recv_offload_first = !handler->recv_offload_first;
>      fat_rwlock_unlock(&dpif->upcall_lock);
>  
>      return error;
> @@ -3211,6 +3248,9 @@ dpif_netlink_recv_wait(struct dpif *dpif_, uint32_t 
> handler_id)
>      } else {
>          dpif_netlink_recv_wait_vport_dispatch(dpif, handler_id);
>      }
> +    if (handler_id == 0) {
> +        netdev_offload_recv_wait();
> +    }
>  #endif
>      fat_rwlock_unlock(&dpif->upcall_lock);
>  }
> diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c
> index fc94078cb..273b576bd 100644
> --- a/ofproto/ofproto-dpif-upcall.c
> +++ b/ofproto/ofproto-dpif-upcall.c
> @@ -840,10 +840,25 @@ recv_upcalls(struct handler *handler)
>              break;
>          }
>  
> -        upcall->fitness = odp_flow_key_to_flow(dupcall->key, 
> dupcall->key_len,
> -                                               flow, NULL);
> -        if (upcall->fitness == ODP_FIT_ERROR) {
> -            goto free_dupcall;
> +        /* If it is normal upcalls, datapath will provide key and key_len
> +         * to construct flow. But for netdev offload upcalls, key and
> +         * key_len are not available. Construct partial flow using available
> +         * info.> +         */
> +        if (dupcall->key && dupcall->key_len) {
> +            upcall->fitness = odp_flow_key_to_flow(dupcall->key,
> +                                                   dupcall->key_len,
> +                                                   flow, NULL);
> +            if (upcall->fitness == ODP_FIT_ERROR) {
> +                goto free_dupcall;
> +            }
> +        } else {
> +            memset(flow, 0, sizeof *flow);
> +            if (dupcall->in_tun) {
> +                memcpy(&flow->tunnel, dupcall->in_tun, sizeof flow->tunnel);
> +            }
> +            flow->in_port.odp_port =
> +                netdev_ifindex_to_odp_port(dupcall->iifindex);

I didn't read the whole set, but this doesn't look right.
In particular, calling netdev_ifindex_to_odp_port() from the generic
upcall processing code.

I agree though that it doesn't make a lot of sense to have a key/key_len
for an sFlow upcall.  A better approach would be to add an actual struct
flow to the dupcall structure.  You're already adding a tunnel metadata
there, we could just add a full flow instead and make offload layer to
prepare it.

In that case recv_upcalls() may check if it has key to parse or it already
has a parsed flow structure.

No HWOL-specific calls like netdev_ifindex_to_odp_port() will be needed
in the generic code then.  And it will be netdev-offload layer's
responsibility to properly fill in a flow structure.


P.S. many patches in this patch set are failing thread-safety analysis.

Best regards, Ilya Maximets.
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