• Eric Dumazet's avatar
    net: SO_INCOMING_CPU setsockopt() support · 70da268b
    Eric Dumazet authored
    SO_INCOMING_CPU as added in commit 2c8c56e1 was a getsockopt() command
    to fetch incoming cpu handling a particular TCP flow after accept()
    This commits adds setsockopt() support and extends SO_REUSEPORT selection
    logic : If a TCP listener or UDP socket has this option set, a packet is
    delivered to this socket only if CPU handling the packet matches the specified
    This allows to build very efficient TCP servers, using one listener per
    RX queue, as the associated TCP listener should only accept flows handled
    in softirq by the same cpu.
    This provides optimal NUMA behavior and keep cpu caches hot.
    Note that __inet_lookup_listener() still has to iterate over the list of
    all listeners. Following patch puts sk_refcnt in a different cache line
    to let this iteration hit only shared and read mostly cache lines.
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
inet_hashtables.c 16.9 KB