From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-131.freemail.mail.aliyun.com (out30-131.freemail.mail.aliyun.com [115.124.30.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CB357A29; Mon, 8 Jul 2024 08:11:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.131 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720426267; cv=none; b=I/UyPahj8OVat1n+TF2keraooSKBDMiHtP4n8bcqcLwaKpmlMYmpCTjVkTEXYaQuBpPgoknPtn2S92j6aAjx//+1M3h8NGWv1XAL27t0njP3TTAaltFiocAE/kDldjH+nDi6v4kAyM7myed2O0mHcMnXNyVwqdpUGepfYJOnRVI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720426267; c=relaxed/simple; bh=tR2QOvwOv5wX8tZJY/QBLViOdPjGlaIRioIgFXAMgL4=; h=Message-ID:Subject:Date:From:To:Cc:References:In-Reply-To: Content-Type; b=Dt782+W97BncqCkeZDl9B+wjlXpamrqVtIMRiivAMUph1yXPyt/Mriin5F8FhhmMK8NnDbZ7DC/3CHe6oi12IW52J+z3QwFauy1ZrgKxZYPCwjD0Qb8hWbMf47TtUEeHU2A0Vf79YETHfi+552ZVeZd89Gn5bosRTO4mgcI02IU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=HoT65ho9; arc=none smtp.client-ip=115.124.30.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="HoT65ho9" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1720426255; h=Message-ID:Subject:Date:From:To:Content-Type; bh=GWsB9SbhmXsK0ZQJnjUR9N8g5i+dYHg7pcDUr4T6FzE=; b=HoT65ho9oeJCPZjXXwIL8JRmyKojOb32q8wuFfo0wqCt4v0hlmvM4YLEjff0MPBZ37kP26w5BFh9uQe5oly7eSKye33q+4pBGBby1rpq3ZgP6H/9+safl1tKwLKDn3lmO8VRLbPftrk+tkbAsp54Jpj69G4xKOBLk/LpWvh7fW8= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037067109;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=14;SR=0;TI=SMTPD_---0WA2Tyo6_1720426254; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0WA2Tyo6_1720426254) by smtp.aliyun-inc.com; Mon, 08 Jul 2024 16:10:55 +0800 Message-ID: <1720426188.2428002-3-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH net-next v7 09/10] virtio_net: xsk: rx: support recv small mode Date: Mon, 8 Jul 2024 16:09:48 +0800 From: Xuan Zhuo To: Jason Wang Cc: netdev@vger.kernel.org, "Michael S. Tsirkin" , =?utf-8?q?Eugenio_P=C3=A9rez?= , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , virtualization@lists.linux.dev, bpf@vger.kernel.org References: <20240705073734.93905-1-xuanzhuo@linux.alibaba.com> <20240705073734.93905-10-xuanzhuo@linux.alibaba.com> <1720424536.972943-1-xuanzhuo@linux.alibaba.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: On Mon, 8 Jul 2024 16:08:44 +0800, Jason Wang wrote: > On Mon, Jul 8, 2024 at 3:47=E2=80=AFPM Xuan Zhuo wrote: > > > > On Mon, 8 Jul 2024 15:00:50 +0800, Jason Wang wro= te: > > > On Fri, Jul 5, 2024 at 3:38=E2=80=AFPM Xuan Zhuo wrote: > > > > > > > > In the process: > > > > 1. We may need to copy data to create skb for XDP_PASS. > > > > 2. We may need to call xsk_buff_free() to release the buffer. > > > > 3. The handle for xdp_buff is difference from the buffer. > > > > > > > > If we pushed this logic into existing receive handle(merge and smal= l), > > > > we would have to maintain code scattered inside merge and small (an= d big). > > > > So I think it is a good choice for us to put the xsk code into an > > > > independent function. > > > > > > > > Signed-off-by: Xuan Zhuo > > > > --- > > > > > > > > v7: > > > > 1. rename xdp_construct_skb to xsk_construct_skb > > > > 2. refactor virtnet_receive() > > > > > > > > drivers/net/virtio_net.c | 176 +++++++++++++++++++++++++++++++++++= ++-- > > > > 1 file changed, 168 insertions(+), 8 deletions(-) > > > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > > index 2b27f5ada64a..64d8cd481890 100644 > > > > --- a/drivers/net/virtio_net.c > > > > +++ b/drivers/net/virtio_net.c > > > > @@ -498,6 +498,12 @@ struct virtio_net_common_hdr { > > > > }; > > > > > > > > static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void = *buf); > > > > +static int virtnet_xdp_handler(struct bpf_prog *xdp_prog, struct x= dp_buff *xdp, > > > > + struct net_device *dev, > > > > + unsigned int *xdp_xmit, > > > > + struct virtnet_rq_stats *stats); > > > > +static void virtnet_receive_done(struct virtnet_info *vi, struct r= eceive_queue *rq, > > > > + struct sk_buff *skb, u8 flags); > > > > > > > > static bool is_xdp_frame(void *ptr) > > > > { > > > > @@ -1062,6 +1068,124 @@ static void sg_fill_dma(struct scatterlist = *sg, dma_addr_t addr, u32 len) > > > > sg->length =3D len; > > > > } > > > > > > > > +static struct xdp_buff *buf_to_xdp(struct virtnet_info *vi, > > > > + struct receive_queue *rq, void *= buf, u32 len) > > > > +{ > > > > + struct xdp_buff *xdp; > > > > + u32 bufsize; > > > > + > > > > + xdp =3D (struct xdp_buff *)buf; > > > > + > > > > + bufsize =3D xsk_pool_get_rx_frame_size(rq->xsk_pool) + vi->= hdr_len; > > > > + > > > > + if (unlikely(len > bufsize)) { > > > > + pr_debug("%s: rx error: len %u exceeds truesize %u\= n", > > > > + vi->dev->name, len, bufsize); > > > > + DEV_STATS_INC(vi->dev, rx_length_errors); > > > > + xsk_buff_free(xdp); > > > > + return NULL; > > > > + } > > > > + > > > > + xsk_buff_set_size(xdp, len); > > > > + xsk_buff_dma_sync_for_cpu(xdp); > > > > + > > > > + return xdp; > > > > +} > > > > + > > > > +static struct sk_buff *xsk_construct_skb(struct receive_queue *rq, > > > > + struct xdp_buff *xdp) > > > > +{ > > > > + unsigned int metasize =3D xdp->data - xdp->data_meta; > > > > + struct sk_buff *skb; > > > > + unsigned int size; > > > > + > > > > + size =3D xdp->data_end - xdp->data_hard_start; > > > > + skb =3D napi_alloc_skb(&rq->napi, size); > > > > + if (unlikely(!skb)) { > > > > + xsk_buff_free(xdp); > > > > + return NULL; > > > > + } > > > > + > > > > + skb_reserve(skb, xdp->data_meta - xdp->data_hard_start); > > > > + > > > > + size =3D xdp->data_end - xdp->data_meta; > > > > + memcpy(__skb_put(skb, size), xdp->data_meta, size); > > > > + > > > > + if (metasize) { > > > > + __skb_pull(skb, metasize); > > > > + skb_metadata_set(skb, metasize); > > > > + } > > > > + > > > > + xsk_buff_free(xdp); > > > > + > > > > + return skb; > > > > +} > > > > + > > > > +static struct sk_buff *virtnet_receive_xsk_small(struct net_device= *dev, struct virtnet_info *vi, > > > > + struct receive_que= ue *rq, struct xdp_buff *xdp, > > > > + unsigned int *xdp_= xmit, > > > > + struct virtnet_rq_= stats *stats) > > > > +{ > > > > + struct bpf_prog *prog; > > > > + u32 ret; > > > > + > > > > + ret =3D XDP_PASS; > > > > + rcu_read_lock(); > > > > + prog =3D rcu_dereference(rq->xdp_prog); > > > > + if (prog) > > > > + ret =3D virtnet_xdp_handler(prog, xdp, dev, xdp_xmi= t, stats); > > > > + rcu_read_unlock(); > > > > + > > > > + switch (ret) { > > > > + case XDP_PASS: > > > > + return xsk_construct_skb(rq, xdp); > > > > + > > > > + case XDP_TX: > > > > + case XDP_REDIRECT: > > > > + return NULL; > > > > + > > > > + default: > > > > + /* drop packet */ > > > > + xsk_buff_free(xdp); > > > > + u64_stats_inc(&stats->drops); > > > > + return NULL; > > > > + } > > > > +} > > > > + > > > > +static void virtnet_receive_xsk_buf(struct virtnet_info *vi, struc= t receive_queue *rq, > > > > + void *buf, u32 len, > > > > + unsigned int *xdp_xmit, > > > > + struct virtnet_rq_stats *stats) > > > > +{ > > > > + struct net_device *dev =3D vi->dev; > > > > + struct sk_buff *skb =3D NULL; > > > > + struct xdp_buff *xdp; > > > > + u8 flags; > > > > + > > > > + len -=3D vi->hdr_len; > > > > + > > > > + u64_stats_add(&stats->bytes, len); > > > > + > > > > + xdp =3D buf_to_xdp(vi, rq, buf, len); > > > > + if (!xdp) > > > > + return; > > > > + > > > > + if (unlikely(len < ETH_HLEN)) { > > > > + pr_debug("%s: short packet %i\n", dev->name, len); > > > > + DEV_STATS_INC(dev, rx_length_errors); > > > > + xsk_buff_free(xdp); > > > > + return; > > > > + } > > > > + > > > > + flags =3D ((struct virtio_net_common_hdr *)(xdp->data - vi-= >hdr_len))->hdr.flags; > > > > + > > > > + if (!vi->mergeable_rx_bufs) > > > > + skb =3D virtnet_receive_xsk_small(dev, vi, rq, xdp,= xdp_xmit, stats); > > > > > > I wonder if we add the mergeable support in the next patch would it be > > > better to re-order the patch? For example, the xsk binding needs to be > > > moved to the last patch, otherwise we break xsk with a mergeable > > > buffer here? > > > > If you worry that the user works with this commit, I want to say you do= not > > worry. > > > > Because the flags NETDEV_XDP_ACT_XSK_ZEROCOPY is not added. I plan to a= dd that > > after the tx is completed. > > Ok, this is something I missed, it would be better to mention it > somewhere (or it is already there but I miss it). OK. I will add it to next version cover. Thanks. > > > > > I do test by adding this flags locally. > > > > Thanks. > > Acked-by: Jason Wang > > Thanks > > > > > > > > > Or anything I missed here? > > > > > > Thanks > > > > > >