• Pavel Tikhomirov's avatar
    sock: allow reading and changing sk_userlocks with setsockopt · 04190bf8
    Pavel Tikhomirov authored
    SOCK_SNDBUF_LOCK and SOCK_RCVBUF_LOCK flags disable automatic socket
    buffers adjustment done by kernel (see tcp_fixup_rcvbuf() and
    tcp_sndbuf_expand()). If we've just created a new socket this adjustment
    is enabled on it, but if one changes the socket buffer size by
    setsockopt(SO_{SND,RCV}BUF*) it becomes disabled.
    
    CRIU needs to call setsockopt(SO_{SND,RCV}BUF*) on each socket on
    restore as it first needs to increase buffer sizes for packet queues
    restore and second it needs to restore back original buffer sizes. So
    after CRIU restore all sockets become non-auto-adjustable, which can
    decrease network performance of restored applications significantly.
    
    CRIU need to be able to restore sockets with enabled/disabled adjustment
    to the same state it was before dump, so let's add special setsockopt
    for it.
    
    Let's also export SOCK_SNDBUF_LOCK and SOCK_RCVBUF_LOCK flags to uAPI so
    that using these interface one can reenable automatic socket buffer
    adjustment on their sockets.
    Signed-off-by: default avatarPavel Tikhomirov <ptikhomirov@virtuozzo.com>
    Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    04190bf8
socket.h 3.78 KB