• Ladi Prosek's avatar
    virtio_ring: Make interrupt suppression spec compliant · 0ea1e4a6
    Ladi Prosek authored
    According to the spec, if the VIRTIO_RING_F_EVENT_IDX feature bit is
    negotiated the driver MUST set flags to 0. Not dirtying the available
    ring in virtqueue_disable_cb also has a minor positive performance
    impact, improving L1 dcache load missed by ~0.5% in vring_bench.
    
    Writes to the used event field (vring_used_event) are still unconditional.
    
    Cc: Michael S. Tsirkin <mst@redhat.com>
    Cc: <stable@vger.kernel.org> # f277ec42 virtio_ring: shadow available
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarLadi Prosek <lprosek@redhat.com>
    Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
    0ea1e4a6
virtio_ring.c 33.2 KB