@@ -6107,6 +6107,17 @@ static int virtnet_alloc_queues(struct virtnet_info *vi)
return -ENOMEM;
}
+static void virtnet_rq_set_premapped(struct virtnet_info *vi)
+{
+ int i;
+
+ for (i = 0; i < vi->max_queue_pairs; i++) {
+ /* error should never happen */
+ BUG_ON(virtqueue_set_dma_premapped(vi->rq[i].vq));
+ vi->rq[i].do_dma = true;
+ }
+}
+
static int init_vqs(struct virtnet_info *vi)
{
int ret;
@@ -6120,6 +6131,10 @@ static int init_vqs(struct virtnet_info *vi)
if (ret)
goto err_free;
+ /* disable for big mode */
+ if (!vi->big_packets || vi->mergeable_rx_bufs)
+ virtnet_rq_set_premapped(vi);
+
cpus_read_lock();
virtnet_set_affinity(vi);
cpus_read_unlock();
Currently, the virtio core will perform a dma operation for each buffer. Although, the same page may be operated multiple times. In premapped mod, we can perform only one dma operation for the pages of the alloc frag. This is beneficial for the iommu device. kernel command line: intel_iommu=on iommu.passthrough=0 | strict=0 | strict=1 Before | 775496pps | 428614pps After | 1109316pps | 742853pps In the 6.11, we disabled this feature because a regress [1]. Now, we fix the problem and re-enable it. [1]: http://lore.kernel.org/all/8b20cc28-45a9-4643-8e87-ba164a540c0a@oracle.com Tested-by: Darren Kenny <darren.kenny@oracle.com> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Acked-by: Jason Wang <jasowang@redhat.com> --- drivers/net/virtio_net.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)