Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756340AbZLKMq5 (ORCPT ); Fri, 11 Dec 2009 07:46:57 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755612AbZLKMqu (ORCPT ); Fri, 11 Dec 2009 07:46:50 -0500 Received: from e8.ny.us.ibm.com ([32.97.182.138]:55770 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754559AbZLKMqt (ORCPT ); Fri, 11 Dec 2009 07:46:49 -0500 Subject: PATCH v2 3/4] Defer skb allocation -- new recvbuf alloc & receive calls From: Shirley Ma To: Rusty Russell Cc: "Michael S. Tsirkin" , Avi Kivity , netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Anthony Liguori In-Reply-To: <1260534506.30371.6.camel@localhost.localdomain> References: <1258697359.7416.14.camel@localhost.localdomain> <200911231123.18898.rusty@rustcorp.com.au> <20091208122134.GA17286@redhat.com> <1260534506.30371.6.camel@localhost.localdomain> Content-Type: text/plain Date: Fri, 11 Dec 2009 04:46:53 -0800 Message-Id: <1260535613.30371.24.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.24.5 (2.24.5-2.fc10) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4342 Lines: 192 Signed-off-by: Shirley Ma ------------- diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 100b4b9..dde8060 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -203,6 +203,73 @@ static struct sk_buff *skb_goodcopy(struct virtnet_info *vi, struct page **page, return skb; } +static struct sk_buff *receive_big(struct virtnet_info *vi, struct page *page, + unsigned int len) +{ + struct sk_buff *skb; + + skb = skb_goodcopy(vi, &page, &len); + if (unlikely(!skb)) + return NULL; + + while (len > 0) { + len = skb_set_frag(skb, page, 0, len); + page = (struct page *)page->private; + } + + if (page) + give_pages(vi, page); + + return skb; +} + +static struct sk_buff *receive_mergeable(struct virtnet_info *vi, + struct page *page, unsigned int len) +{ + struct sk_buff *skb; + struct skb_vnet_hdr *hdr; + int num_buf, i; + + if (len > PAGE_SIZE) + len = PAGE_SIZE; + + skb = skb_goodcopy(vi, &page, &len); + + if (unlikely(!skb)) + return NULL; + + hdr = skb_vnet_hdr(skb); + num_buf = hdr->mhdr.num_buffers; + while (--num_buf) { + struct page *page; + + i = skb_shinfo(skb)->nr_frags; + if (i >= MAX_SKB_FRAGS) { + pr_debug("%s: packet too long %d\n", skb->dev->name, + len); + skb->dev->stats.rx_length_errors++; + return skb; + } + + page = vi->rvq->vq_ops->get_buf(vi->rvq, &len); + if (!page) { + pr_debug("%s: rx error: %d buffers missing\n", + skb->dev->name, hdr->mhdr.num_buffers); + skb->dev->stats.rx_length_errors++; + return skb; + } + + if (len > PAGE_SIZE) + len = PAGE_SIZE; + + skb_set_frag(skb, page, 0, len); + + vi->num--; + } + + return skb; +} + static void receive_skb(struct net_device *dev, struct sk_buff *skb, unsigned len) { @@ -356,6 +423,103 @@ drop: dev_kfree_skb(skb); } +static int add_recvbuf_small(struct virtnet_info *vi, gfp_t gfp, bool *oom) +{ + struct sk_buff *skb; + struct skb_vnet_hdr *hdr; + struct scatterlist sg[2]; + int err = 0; + + skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN + NET_IP_ALIGN); + if (unlikely(!skb)) { + *oom = true; + return err; + } + + skb_reserve(skb, NET_IP_ALIGN); + skb_put(skb, MAX_PACKET_LEN); + + hdr = skb_vnet_hdr(skb); + sg_set_buf(sg, &hdr->hdr, sizeof(hdr->hdr)); + + skb_to_sgvec(skb, sg+1, 0, skb->len); + + err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, 2, skb); + if (err < 0) + kfree_skb(skb); + else + skb_queue_head(&vi->recv, skb); + + return err; +} + +static int add_recvbuf_big(struct virtnet_info *vi, gfp_t gfp, bool *oom) +{ + struct scatterlist sg[2 + MAX_SKB_FRAGS]; + int total = MAX_SKB_FRAGS + 2; + char *p; + int err = 0; + int i, offset; + struct page *first = NULL; + struct page *page; + /* share one page between virtio_net header and data */ + struct padded_vnet_hdr { + struct virtio_net_hdr hdr; + /* This padding makes our data 16 byte aligned */ + char padding[6]; + }; + + offset = sizeof(struct padded_vnet_hdr); + + for (i = total - 1; i > 0; i--) { + page = get_a_page(vi, gfp); + if (!page) { + if (first) + give_pages(vi, first); + *oom = true; + break; + } + + p = page_address(page); + page->private = (unsigned long)first; + first = page; + + /* allocate MAX_SKB_FRAGS + 1 pages for big packets */ + if (i == 1) { + sg_set_buf(&sg[i-1], p, sizeof(struct virtio_net_hdr)); + sg_set_buf(&sg[i], p + offset, PAGE_SIZE - offset); + err = vi->rvq->vq_ops->add_buf(vi->rvq, sg, 0, total, + first); + if (err < 0) + give_pages(vi, first); + } else + sg_set_buf(&sg[i], p, PAGE_SIZE); + } + + return err; +} + +static int add_recvbuf_mergeable(struct virtnet_info *vi, gfp_t gfp, bool *oom) +{ + struct page *page; + struct scatterlist sg; + int err = 0; + + page = get_a_page(vi, gfp); + if (!page) { + *oom = true; + return err; + } + + sg_init_one(&sg, page_address(page), PAGE_SIZE); + + err = vi->rvq->vq_ops->add_buf(vi->rvq, &sg, 0, 1, page); + if (err < 0) + give_pages(vi, page); + + return err; +} + static bool try_fill_recv_maxbufs(struct virtnet_info *vi, gfp_t gfp) { struct sk_buff *skb; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/