From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-100.freemail.mail.aliyun.com (out30-100.freemail.mail.aliyun.com [115.124.30.100]) (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 193C21F934; Mon, 26 Feb 2024 11:33:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.100 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708947233; cv=none; b=DvdM2k4O4vvNKnPkj59BcBIxPEfZNrbBtswPG/fpb6PwDmRkDh/gXshlvZDark4CXWAn1i2AH9rdcCEdhYL3c72+jBMZqlhulcrGjR+lYtTY7St6l9r3/vrjBjkFeowgZRksLaql0ZGwBUW6LcP0vSFN/asVwBFjdXpjITOcjjk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708947233; c=relaxed/simple; bh=xlKjo1EaB8Z1zUKsHGTiu1yBB0mXOXetK5n8/uZWvv0=; h=Message-ID:Subject:Date:From:To:Cc:References:In-Reply-To; b=nOGfipamuU1nb1M40TqogiTqeh8GVZJeyDAF9fITdnSDNl6e0m6TvnMcasyYkBTPSfW9ZKznJelMtHyz6IgDsMo12WddwX6/h6dyKTQakL9WgB2R+5i5Gr5L3nj56wcW9juEUABIVPrtt5loVRYBjC44yl88DoaArgBdZxBLIgs= 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=F5uupeh1; arc=none smtp.client-ip=115.124.30.100 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="F5uupeh1" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1708947227; h=Message-ID:Subject:Date:From:To; bh=PA5rSrpl64WnpD9JFRR8X4sLHOqcBZqQNcSxg5sFIRA=; b=F5uupeh1XtYj9e6nYLhYCskx0+i2ZZ0AKnjHeTwNLzyt3Mpz5sF6GF7BSWEq5f84bjlVe39vhjFNe2DKJutXYVeOehTbQLwDmOiUVrjiX7UtB/U8k9NoZzWD1kw977ahIbb+bCvd5AAWpiIExsyDUnMsNOfjgCwG/wrYjxUuEhE= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R691e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046060;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=35;SR=0;TI=SMTPD_---0W1Hkq0s_1708947223; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0W1Hkq0s_1708947223) by smtp.aliyun-inc.com; Mon, 26 Feb 2024 19:33:45 +0800 Message-ID: <1708947209.1148863-1-xuanzhuo@linux.alibaba.com> Subject: Re: [PATCH vhost v2 19/19] virtio_net: sq support premapped mode Date: Mon, 26 Feb 2024 19:33:29 +0800 From: Xuan Zhuo To: "Michael S. Tsirkin" Cc: virtualization@lists.linux.dev, Richard Weinberger , Anton Ivanov , Johannes Berg , Jason Wang , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Hans de Goede , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Vadim Pasternak , Bjorn Andersson , Mathieu Poirier , Cornelia Huck , Halil Pasic , Eric Farman , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , linux-um@lists.infradead.org, netdev@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, kvm@vger.kernel.org, bpf@vger.kernel.org, Christoph Hellwig References: <20240223082726.52915-1-xuanzhuo@linux.alibaba.com> <20240223082726.52915-20-xuanzhuo@linux.alibaba.com> <20240225032330-mutt-send-email-mst@kernel.org> <1708946440.799724-1-xuanzhuo@linux.alibaba.com> <20240226063120-mutt-send-email-mst@kernel.org> In-Reply-To: <20240226063120-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: linux-remoteproc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: On Mon, 26 Feb 2024 06:31:49 -0500, "Michael S. Tsirkin" wrote: > On Mon, Feb 26, 2024 at 07:20:40PM +0800, Xuan Zhuo wrote: > > On Sun, 25 Feb 2024 03:38:48 -0500, "Michael S. Tsirkin" wrote: > > > On Fri, Feb 23, 2024 at 04:27:26PM +0800, Xuan Zhuo wrote: > > > > If the xsk is enabling, the xsk tx will share the send queue. > > > > But the xsk requires that the send queue use the premapped mode. > > > > So the send queue must support premapped mode. > > > > > > > > cmd: > > > > sh samples/pktgen/pktgen_sample01_simple.sh -i eth0 \ > > > > -s 16 -d 10.0.0.128 -m 00:16:3e:2c:c8:2e -n 0 -p 100 > > > > CPU: > > > > Intel(R) Xeon(R) Platinum 8369B CPU @ 2.70GHz > > > > > > > > Machine: > > > > ecs.g7.2xlarge(Aliyun) > > > > > > > > before: 1600010.00 > > > > after(no-premapped): 1599966.00 > > > > after(premapped): 1600014.00 > > > > > > > > Signed-off-by: Xuan Zhuo > > > > --- > > > > drivers/net/virtio_net.c | 136 +++++++++++++++++++++++++++++++++++++-- > > > > 1 file changed, 132 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > > > index 7715bb7032ec..b83ef6afc4fb 100644 > > > > --- a/drivers/net/virtio_net.c > > > > +++ b/drivers/net/virtio_net.c > > > > @@ -146,6 +146,25 @@ struct virtnet_rq_dma { > > > > u16 need_sync; > > > > }; > > > > > > > > +struct virtnet_sq_dma { > > > > + union { > > > > + struct virtnet_sq_dma *next; > > > > + void *data; > > > > + }; > > > > + > > > > + u32 num; > > > > + > > > > + dma_addr_t addr[MAX_SKB_FRAGS + 2]; > > > > + u32 len[MAX_SKB_FRAGS + 2]; > > > > +}; > > > > + > > > > +struct virtnet_sq_dma_head { > > > > + /* record for kfree */ > > > > + void *p; > > > > + > > > > + struct virtnet_sq_dma *free; > > > > +}; > > > > + > > > > /* Internal representation of a send virtqueue */ > > > > struct send_queue { > > > > /* Virtqueue associated with this send _queue */ > > > > @@ -165,6 +184,8 @@ struct send_queue { > > > > > > > > /* Record whether sq is in reset state. */ > > > > bool reset; > > > > + > > > > + struct virtnet_sq_dma_head dmainfo; > > > > }; > > > > > > > > /* Internal representation of a receive virtqueue */ > > > > @@ -368,6 +389,95 @@ static struct xdp_frame *ptr_to_xdp(void *ptr) > > > > return (struct xdp_frame *)((unsigned long)ptr & ~VIRTIO_XDP_FLAG); > > > > } > > > > > > > > +static struct virtnet_sq_dma *virtnet_sq_unmap(struct send_queue *sq, void **data) > > > > +{ > > > > + struct virtnet_sq_dma *d; > > > > + int i; > > > > + > > > > + d = *data; > > > > + *data = d->data; > > > > + > > > > + for (i = 0; i < d->num; ++i) > > > > + virtqueue_dma_unmap_page_attrs(sq->vq, d->addr[i], d->len[i], > > > > + DMA_TO_DEVICE, 0); > > > > + > > > > + d->next = sq->dmainfo.free; > > > > + sq->dmainfo.free = d; > > > > + > > > > + return d; > > > > +} > > > > + > > > > +static struct virtnet_sq_dma *virtnet_sq_map_sg(struct send_queue *sq, > > > > + int nents, void *data) > > > > +{ > > > > + struct virtnet_sq_dma *d; > > > > + struct scatterlist *sg; > > > > + int i; > > > > + > > > > + if (!sq->dmainfo.free) > > > > + return NULL; > > > > + > > > > + d = sq->dmainfo.free; > > > > + sq->dmainfo.free = d->next; > > > > + > > > > + for_each_sg(sq->sg, sg, nents, i) { > > > > + if (virtqueue_dma_map_sg_attrs(sq->vq, sg, DMA_TO_DEVICE, 0)) > > > > + goto err; > > > > + > > > > + d->addr[i] = sg->dma_address; > > > > + d->len[i] = sg->length; > > > > + } > > > > + > > > > + d->data = data; > > > > + d->num = i; > > > > + return d; > > > > + > > > > +err: > > > > + d->num = i; > > > > + virtnet_sq_unmap(sq, (void **)&d); > > > > + return NULL; > > > > +} > > > > > > > > > Do I see a reimplementation of linux/llist.h here? > > > > > > > > > > + > > > > +static int virtnet_add_outbuf(struct send_queue *sq, u32 num, void *data) > > > > +{ > > > > + int ret; > > > > + > > > > + if (sq->vq->premapped) { > > > > + data = virtnet_sq_map_sg(sq, num, data); > > > > + if (!data) > > > > + return -ENOMEM; > > > > + } > > > > + > > > > + ret = virtqueue_add_outbuf(sq->vq, sq->sg, num, data, GFP_ATOMIC); > > > > + if (ret && sq->vq->premapped) > > > > + virtnet_sq_unmap(sq, &data); > > > > + > > > > + return ret; > > > > +} > > > > + > > > > +static int virtnet_sq_init_dma_mate(struct send_queue *sq) > > > > > > Mate? The popular south african drink? > > > > > > > +{ > > > > + struct virtnet_sq_dma *d; > > > > + int num, i; > > > > + > > > > + num = virtqueue_get_vring_size(sq->vq); > > > > + > > > > + sq->dmainfo.free = kcalloc(num, sizeof(*sq->dmainfo.free), GFP_KERNEL); > > > > + if (!sq->dmainfo.free) > > > > + return -ENOMEM; > > > > > > > > > This could be quite a bit of memory for a large queue. And for a bunch > > > of common cases where unmap is a nop (e.g. iommu pt) this does nothing > > > useful at all. And also, this does nothing useful if PLATFORM_ACCESS is off > > > which is super common. > > > > > > A while ago I proposed: > > > - extend DMA APIs so one can query whether unmap is a nop > > > > I think such code is ok: > > > > bool dma_is_direct(struct device *dev) > > { > > if (!dma_map_direct(dev, ops)) > > return false; > > what is dma_map_direct? can't find it in the tree. YES. diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 58db8fd70471..5a8f7a927aa1 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -144,6 +144,18 @@ static inline bool dma_map_direct(struct device *dev, return dma_go_direct(dev, *dev->dma_mask, ops); } +bool dma_is_direct(struct device *dev) +{ + if (!dma_map_direct(dev, ops)) + return false; + + if (is_swiotlb_force_bounce(dev)) + return false; + + return true; +} +EXPORT_SYMBOL(dma_unmap_page_attrs); + Thanks. > > > if (is_swiotlb_force_bounce(dev)) > > return false; > > > > return true; > > } > > > > @Christoph Hellwig > > > > Thanks. > > > > > > > and whether sync is a nop > > > - virtio wrapper taking into account PLATFORM_ACCESS too > > > > > > then we can save all this work and memory when not needed. > > > > > > > > > > > > > + > > > > + sq->dmainfo.p = sq->dmainfo.free; > > > > + > > > > + for (i = 0; i < num; ++i) { > > > > + d = &sq->dmainfo.free[i]; > > > > + d->next = d + 1; > > > > + } > > > > + > > > > + d->next = NULL; > > > > + > > > > + return 0; > > > > +} > > > > + > > > > static void __free_old_xmit(struct send_queue *sq, bool in_napi, > > > > struct virtnet_sq_free_stats *stats) > > > > { > > > > @@ -377,6 +487,9 @@ static void __free_old_xmit(struct send_queue *sq, bool in_napi, > > > > while ((ptr = virtqueue_get_buf(sq->vq, &len)) != NULL) { > > > > ++stats->packets; > > > > > > > > + if (sq->vq->premapped) > > > > + virtnet_sq_unmap(sq, &ptr); > > > > + > > > > if (!is_xdp_frame(ptr)) { > > > > struct sk_buff *skb = ptr; > > > > > > > > @@ -890,8 +1003,7 @@ static int __virtnet_xdp_xmit_one(struct virtnet_info *vi, > > > > skb_frag_size(frag), skb_frag_off(frag)); > > > > } > > > > > > > > - err = virtqueue_add_outbuf(sq->vq, sq->sg, nr_frags + 1, > > > > - xdp_to_ptr(xdpf), GFP_ATOMIC); > > > > + err = virtnet_add_outbuf(sq, nr_frags + 1, xdp_to_ptr(xdpf)); > > > > if (unlikely(err)) > > > > return -ENOSPC; /* Caller handle free/refcnt */ > > > > > > > > @@ -2357,7 +2469,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) > > > > return num_sg; > > > > num_sg++; > > > > } > > > > - return virtqueue_add_outbuf(sq->vq, sq->sg, num_sg, skb, GFP_ATOMIC); > > > > + return virtnet_add_outbuf(sq, num_sg, skb); > > > > } > > > > > > > > static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > > > > @@ -4166,6 +4278,8 @@ static void virtnet_free_queues(struct virtnet_info *vi) > > > > for (i = 0; i < vi->max_queue_pairs; i++) { > > > > __netif_napi_del(&vi->rq[i].napi); > > > > __netif_napi_del(&vi->sq[i].napi); > > > > + > > > > + kfree(vi->sq[i].dmainfo.p); > > > > } > > > > > > > > /* We called __netif_napi_del(), > > > > @@ -4214,6 +4328,15 @@ static void free_receive_page_frags(struct virtnet_info *vi) > > > > > > > > static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf) > > > > { > > > > + struct virtnet_info *vi = vq->vdev->priv; > > > > + struct send_queue *sq; > > > > + int i = vq2rxq(vq); > > > > + > > > > + sq = &vi->sq[i]; > > > > + > > > > + if (sq->vq->premapped) > > > > + virtnet_sq_unmap(sq, &buf); > > > > + > > > > if (!is_xdp_frame(buf)) > > > > dev_kfree_skb(buf); > > > > else > > > > @@ -4327,8 +4450,10 @@ static int virtnet_find_vqs(struct virtnet_info *vi) > > > > if (ctx) > > > > ctx[rxq2vq(i)] = true; > > > > > > > > - if (premapped) > > > > + if (premapped) { > > > > premapped[rxq2vq(i)] = true; > > > > + premapped[txq2vq(i)] = true; > > > > + } > > > > } > > > > > > > > cfg.nvqs = total_vqs; > > > > @@ -4352,6 +4477,9 @@ static int virtnet_find_vqs(struct virtnet_info *vi) > > > > vi->rq[i].vq = vqs[rxq2vq(i)]; > > > > vi->rq[i].min_buf_len = mergeable_min_buf_len(vi, vi->rq[i].vq); > > > > vi->sq[i].vq = vqs[txq2vq(i)]; > > > > + > > > > + if (vi->sq[i].vq->premapped) > > > > + virtnet_sq_init_dma_mate(&vi->sq[i]); > > > > } > > > > > > > > /* run here: ret == 0. */ > > > > -- > > > > 2.32.0.3.g01195cf9f > > > >