From patchwork Fri Feb 22 14:55:18 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jason Wang X-Patchwork-Id: 1046972 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 445Zj23T5Nz9s5c for ; Sat, 23 Feb 2019 02:17:58 +1100 (AEDT) Received: from localhost ([127.0.0.1]:52510 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gxCaK-00080a-9g for incoming@patchwork.ozlabs.org; Fri, 22 Feb 2019 10:17:56 -0500 Received: from eggs.gnu.org ([209.51.188.92]:34995) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gxCHH-0000VB-42 for qemu-devel@nongnu.org; Fri, 22 Feb 2019 09:58:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gxCF6-0007fa-A2 for qemu-devel@nongnu.org; Fri, 22 Feb 2019 09:56:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34220) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gxCF5-0007Ck-SK for qemu-devel@nongnu.org; Fri, 22 Feb 2019 09:56:00 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 919695D61F; Fri, 22 Feb 2019 14:55:55 +0000 (UTC) Received: from jason-ThinkPad-T430s.redhat.com (ovpn-12-32.pek2.redhat.com [10.72.12.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id DB9541A7CD; Fri, 22 Feb 2019 14:55:53 +0000 (UTC) From: Jason Wang To: qemu-devel@nongnu.org, peter.maydell@linaro.org Date: Fri, 22 Feb 2019 22:55:18 +0800 Message-Id: <1550847320-25110-12-git-send-email-jasowang@redhat.com> In-Reply-To: <1550847320-25110-1-git-send-email-jasowang@redhat.com> References: <1550847320-25110-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 22 Feb 2019 14:55:55 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 11/13] net: netmap: small improvements netmap_send() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jason Wang , Vincenzo Maffione Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Vincenzo Maffione This change improves the handling of incomplete multi-slot packets (e.g. with the NS_MOREFRAG set), by advancing ring->head only on complete packets. The ring->cur pointer is advanced in any case in order to acknowledge the kernel and move the wake-up point (thus avoiding repeated wake-ups). Also don't be verbose when incomplete packets are found. Signed-off-by: Vincenzo Maffione Signed-off-by: Jason Wang --- net/netmap.c | 31 +++++++++++++++++++------------ 1 file changed, 19 insertions(+), 12 deletions(-) diff --git a/net/netmap.c b/net/netmap.c index 2d11a8f..71a8122 100644 --- a/net/netmap.c +++ b/net/netmap.c @@ -272,39 +272,46 @@ static void netmap_send(void *opaque) { NetmapState *s = opaque; struct netmap_ring *ring = s->rx; + unsigned int tail = ring->tail; - /* Keep sending while there are available packets into the netmap + /* Keep sending while there are available slots in the netmap RX ring and the forwarding path towards the peer is open. */ - while (!nm_ring_empty(ring)) { - uint32_t i; + while (ring->head != tail) { + uint32_t i = ring->head; uint32_t idx; bool morefrag; int iovcnt = 0; int iovsize; + /* Get a (possibly multi-slot) packet. */ do { - i = ring->cur; idx = ring->slot[i].buf_idx; morefrag = (ring->slot[i].flags & NS_MOREFRAG); - s->iov[iovcnt].iov_base = (u_char *)NETMAP_BUF(ring, idx); + s->iov[iovcnt].iov_base = (void *)NETMAP_BUF(ring, idx); s->iov[iovcnt].iov_len = ring->slot[i].len; iovcnt++; + i = nm_ring_next(ring, i); + } while (i != tail && morefrag); - ring->cur = ring->head = nm_ring_next(ring, i); - } while (!nm_ring_empty(ring) && morefrag); + /* Advance ring->cur to tell the kernel that we have seen the slots. */ + ring->cur = i; - if (unlikely(nm_ring_empty(ring) && morefrag)) { - RD(5, "[netmap_send] ran out of slots, with a pending" - "incomplete packet\n"); + if (unlikely(morefrag)) { + /* This is a truncated packet, so we can stop without releasing the + * incomplete slots by updating ring->head. We will hopefully + * re-read the complete packet the next time we are called. */ + break; } iovsize = qemu_sendv_packet_async(&s->nc, s->iov, iovcnt, netmap_send_completed); + /* Release the slots to the kernel. */ + ring->head = i; + if (iovsize == 0) { /* The peer does not receive anymore. Packet is queued, stop - * reading from the backend until netmap_send_completed() - */ + * reading from the backend until netmap_send_completed(). */ netmap_read_poll(s, false); break; }