From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [net-next v2] virtio_net: replace netdev_alloc_skb_ip_align() with napi_alloc_skb() Date: Sun, 20 Mar 2016 14:28:23 +0200 Message-ID: <20160320142551-mutt-send-email-mst@redhat.com> References: <98c94ca899603eb4212c44aa1a658825198ed49a.1458290241.git.pabeni@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, Hannes Frederic Sowa , Venkatesh Srinivas To: Paolo Abeni Return-path: Received: from mx1.redhat.com ([209.132.183.28]:51539 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755227AbcCTM21 (ORCPT ); Sun, 20 Mar 2016 08:28:27 -0400 Content-Disposition: inline In-Reply-To: <98c94ca899603eb4212c44aa1a658825198ed49a.1458290241.git.pabeni@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Mar 18, 2016 at 04:42:48PM +0100, Paolo Abeni wrote: > This gives small but noticeable rx performance improvement (2-3%) > and will allow exploiting future napi improvement. > > Signed-off-by: Paolo Abeni I am not sure this is necessarily worth doing for this dumb hardware. I queued v1 in vhost tree for now, let's see some performance numbers before we start changing about other paths. > -- > v2: replace also netdev_alloc_skb_ip_align() invocation in > add_recvbuf_small(), suggested by Venkatesh Srinivas > --- > drivers/net/virtio_net.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index fb0eae4..100e039 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -260,7 +260,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > p = page_address(page) + offset; > > /* copy small packet so we can reuse these pages for small data */ > - skb = netdev_alloc_skb_ip_align(vi->dev, GOOD_COPY_LEN); > + skb = napi_alloc_skb(&rq->napi, GOOD_COPY_LEN); > if (unlikely(!skb)) > return NULL; > > @@ -541,7 +541,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq, > struct virtio_net_hdr_mrg_rxbuf *hdr; > int err; > > - skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp); > + skb = __napi_alloc_skb(&rq->napi, GOOD_PACKET_LEN, gfp); > if (unlikely(!skb)) > return -ENOMEM; > > -- > 1.8.3.1