• Jason Wang's avatar
    vhost_net: mitigate page reference counting during page frag refill · e4dab1e6
    Jason Wang authored
    We do a get_page() which involves a atomic operation. This patch tries
    to mitigate a per packet atomic operation by maintaining a reference
    bias which is initially USHRT_MAX. Each time a page is got, instead of
    calling get_page() we decrease the bias and when we find it's time to
    use a new page we will decrease the bias at one time through
    __page_cache_drain_cache().
    
    Testpmd(virtio_user + vhost_net) + XDP_DROP on TAP shows about 1.6%
    improvement.
    
    Before: 4.63Mpps
    After:  4.71Mpps
    Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    e4dab1e6
net.c 44.6 KB