From patchwork Mon Mar 30 04:08:42 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KY Srinivasan X-Patchwork-Id: 455968 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 7E241140140 for ; Mon, 30 Mar 2015 13:52:00 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752860AbbC3Cvi (ORCPT ); Sun, 29 Mar 2015 22:51:38 -0400 Received: from p3plsmtps2ded03.prod.phx3.secureserver.net ([208.109.80.60]:60866 "EHLO p3plsmtps2ded03.prod.phx3.secureserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752631AbbC3Cvf (ORCPT ); Sun, 29 Mar 2015 22:51:35 -0400 Received: from linuxonhyperv.com ([72.167.245.219]) by p3plsmtps2ded03.prod.phx3.secureserver.net with : DED : id 9era1q03H4kklxU01eraJf; Sun, 29 Mar 2015 19:51:35 -0700 x-originating-ip: 72.167.245.219 Received: by linuxonhyperv.com (Postfix, from userid 507) id 00BA6190823; Sun, 29 Mar 2015 21:08:43 -0700 (PDT) From: "K. Y. Srinivasan" To: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, jasowang@redhat.com Cc: "K. Y. Srinivasan" Subject: [PATCH net-next 2/2] hv_netvsc: Eliminate memory allocation in the packet send path Date: Sun, 29 Mar 2015 21:08:42 -0700 Message-Id: <1427688522-27991-2-git-send-email-kys@microsoft.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1427688522-27991-1-git-send-email-kys@microsoft.com> References: <1427688478-27950-1-git-send-email-kys@microsoft.com> <1427688522-27991-1-git-send-email-kys@microsoft.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The network protocol used to communicate with the host is the remote ndis (rndis) protocol. We need to decorate each outgoing packet with a rndis header and additional rndis state (rndis per-packet state). To manage this state, we currently allocate memory in the transmit path. Eliminate this allocation by requesting additional head room in the skb. Signed-off-by: K. Y. Srinivasan --- drivers/net/hyperv/hyperv_net.h | 3 +- drivers/net/hyperv/netvsc.c | 10 ++++-- drivers/net/hyperv/netvsc_drv.c | 67 +++++++++++++++++++++++++++---------- drivers/net/hyperv/rndis_filter.c | 2 + 4 files changed, 60 insertions(+), 22 deletions(-) diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h index 384f057..309adee 100644 --- a/drivers/net/hyperv/hyperv_net.h +++ b/drivers/net/hyperv/hyperv_net.h @@ -128,6 +128,7 @@ struct ndis_tcp_ip_checksum_info; struct hv_netvsc_packet { /* Bookkeeping stuff */ u32 status; + bool part_of_skb; struct hv_device *device; bool is_data_pkt; @@ -150,7 +151,7 @@ struct hv_netvsc_packet { /* Points to the send/receive buffer where the ethernet frame is */ void *data; u32 page_buf_cnt; - struct hv_page_buffer page_buf[0]; + struct hv_page_buffer *page_buf; }; struct netvsc_device_info { diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c index ecbd813..f699236 100644 --- a/drivers/net/hyperv/netvsc.c +++ b/drivers/net/hyperv/netvsc.c @@ -866,11 +866,15 @@ int netvsc_send(struct hv_device *device, netvsc_copy_to_send_buf(net_device, section_index, msd_len, packet); - skb = (struct sk_buff *) - (unsigned long)packet->send_completion_tid; + if (!packet->part_of_skb) { + skb = (struct sk_buff *) + (unsigned long) + packet->send_completion_tid; + + packet->send_completion_tid = 0; + } packet->page_buf_cnt = 0; - packet->send_completion_tid = 0; packet->send_buf_index = section_index; packet->total_data_buflen += msd_len; diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 75beb89..f9db6bc 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -235,7 +235,8 @@ static void netvsc_xmit_completion(void *context) struct sk_buff *skb = (struct sk_buff *) (unsigned long)packet->send_completion_tid; - kfree(packet); + if (!packet->part_of_skb) + kfree(packet); if (skb) dev_kfree_skb_any(skb); @@ -383,6 +384,9 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net) u32 net_trans_info; u32 hash; u32 skb_length = skb->len; + u32 head_room = skb_headroom(skb); + u32 pkt_sz; + struct hv_page_buffer page_buf[MAX_PAGE_BUFFER_COUNT]; /* We will atmost need two pages to describe the rndis @@ -397,24 +401,32 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net) return NETDEV_TX_OK; } - /* Allocate a netvsc packet based on # of frags. */ - packet = kzalloc(sizeof(struct hv_netvsc_packet) + - (num_data_pgs * sizeof(struct hv_page_buffer)) + - sizeof(struct rndis_message) + - NDIS_VLAN_PPI_SIZE + NDIS_CSUM_PPI_SIZE + - NDIS_LSO_PPI_SIZE + NDIS_HASH_PPI_SIZE, GFP_ATOMIC); - if (!packet) { - /* out of memory, drop packet */ - netdev_err(net, "unable to allocate hv_netvsc_packet\n"); - - dev_kfree_skb(skb); - net->stats.tx_dropped++; - return NETDEV_TX_OK; + pkt_sz = sizeof(struct hv_netvsc_packet) + + sizeof(struct rndis_message) + + NDIS_VLAN_PPI_SIZE + NDIS_CSUM_PPI_SIZE + + NDIS_LSO_PPI_SIZE + NDIS_HASH_PPI_SIZE; + + if (head_room < pkt_sz) { + packet = kmalloc(pkt_sz, GFP_ATOMIC); + if (!packet) { + /* out of memory, drop packet */ + netdev_err(net, "unable to alloc hv_netvsc_packet\n"); + dev_kfree_skb(skb); + net->stats.tx_dropped++; + return NETDEV_TX_OK; + } + packet->part_of_skb = false; + } else { + /* Use the headroom for building up the packet */ + packet = (struct hv_netvsc_packet *)skb->head; + packet->part_of_skb = true; } + packet->status = 0; packet->xmit_more = skb->xmit_more; packet->vlan_tci = skb->vlan_tci; + packet->page_buf = page_buf; packet->q_idx = skb_get_queue_mapping(skb); @@ -422,8 +434,13 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net) packet->total_data_buflen = skb->len; packet->rndis_msg = (struct rndis_message *)((unsigned long)packet + - sizeof(struct hv_netvsc_packet) + - (num_data_pgs * sizeof(struct hv_page_buffer))); + sizeof(struct hv_netvsc_packet)); + + memset(packet->rndis_msg, 0, sizeof(struct rndis_message) + + NDIS_VLAN_PPI_SIZE + + NDIS_CSUM_PPI_SIZE + + NDIS_LSO_PPI_SIZE + + NDIS_HASH_PPI_SIZE); /* Set the completion routine */ packet->send_completion = netvsc_xmit_completion; @@ -555,7 +572,7 @@ do_send: rndis_msg->msg_len += rndis_msg_size; packet->total_data_buflen = rndis_msg->msg_len; packet->page_buf_cnt = init_page_array(rndis_msg, rndis_msg_size, - skb, &packet->page_buf[0]); + skb, &page_buf[0]); ret = netvsc_send(net_device_ctx->device_ctx, packet); @@ -564,7 +581,8 @@ drop: net->stats.tx_bytes += skb_length; net->stats.tx_packets++; } else { - kfree(packet); + if (!packet->part_of_skb) + kfree(packet); if (ret != -EAGAIN) { dev_kfree_skb_any(skb); net->stats.tx_dropped++; @@ -846,12 +864,18 @@ static int netvsc_probe(struct hv_device *dev, struct netvsc_device_info device_info; struct netvsc_device *nvdev; int ret; + u32 max_needed_headroom; net = alloc_etherdev_mq(sizeof(struct net_device_context), num_online_cpus()); if (!net) return -ENOMEM; + max_needed_headroom = sizeof(struct hv_netvsc_packet) + + sizeof(struct rndis_message) + + NDIS_VLAN_PPI_SIZE + NDIS_CSUM_PPI_SIZE + + NDIS_LSO_PPI_SIZE + NDIS_HASH_PPI_SIZE; + netif_carrier_off(net); net_device_ctx = netdev_priv(net); @@ -870,6 +894,13 @@ static int netvsc_probe(struct hv_device *dev, net->ethtool_ops = ðtool_ops; SET_NETDEV_DEV(net, &dev->device); + /* + * Request additional head room in the skb. + * We will use this space to build the rndis + * heaser and other state we need to maintain. + */ + net->needed_headroom = max_needed_headroom; + /* Notify the netvsc driver of the new device */ device_info.ring_size = ring_size; ret = rndis_filter_device_add(dev, &device_info); diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c index fdfab1f..a160437 100644 --- a/drivers/net/hyperv/rndis_filter.c +++ b/drivers/net/hyperv/rndis_filter.c @@ -210,6 +210,7 @@ static int rndis_filter_send_request(struct rndis_device *dev, { int ret; struct hv_netvsc_packet *packet; + struct hv_page_buffer page_buf[2]; /* Setup the packet to send it */ packet = &req->pkt; @@ -217,6 +218,7 @@ static int rndis_filter_send_request(struct rndis_device *dev, packet->is_data_pkt = false; packet->total_data_buflen = req->request_msg.msg_len; packet->page_buf_cnt = 1; + packet->page_buf = page_buf; packet->page_buf[0].pfn = virt_to_phys(&req->request_msg) >> PAGE_SHIFT;