From nobody Wed Apr 16 11:36:24 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1551770067558630.5220411898771; Mon, 4 Mar 2019 23:14:27 -0800 (PST) Received: from localhost ([127.0.0.1]:38609 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h14HO-0003fR-Ga for importer@patchew.org; Tue, 05 Mar 2019 02:14:22 -0500 Received: from eggs.gnu.org ([209.51.188.92]:43361) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h14Fe-0002cf-Qx for qemu-devel@nongnu.org; Tue, 05 Mar 2019 02:12:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h14Fc-0000WG-IO for qemu-devel@nongnu.org; Tue, 05 Mar 2019 02:12:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36284) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h14Fb-0000Rk-1a for qemu-devel@nongnu.org; Tue, 05 Mar 2019 02:12:32 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 184923082E4B; Tue, 5 Mar 2019 07:12:29 +0000 (UTC) Received: from jason-ThinkPad-T430s.redhat.com (ovpn-12-234.pek2.redhat.com [10.72.12.234]) by smtp.corp.redhat.com (Postfix) with ESMTP id 101A618009; Tue, 5 Mar 2019 07:12:26 +0000 (UTC) From: Jason Wang To: qemu-devel@nongnu.org, peter.maydell@linaro.org Date: Tue, 5 Mar 2019 15:12:09 +0800 Message-Id: <1551769940-22739-3-git-send-email-jasowang@redhat.com> In-Reply-To: <1551769940-22739-1-git-send-email-jasowang@redhat.com> References: <1551769940-22739-1-git-send-email-jasowang@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Tue, 05 Mar 2019 07:12:29 +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 V2 02/13] 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+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" 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 =3D opaque; struct netmap_ring *ring =3D s->rx; + unsigned int tail =3D ring->tail; =20 - /* 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 !=3D tail) { + uint32_t i =3D ring->head; uint32_t idx; bool morefrag; int iovcnt =3D 0; int iovsize; =20 + /* Get a (possibly multi-slot) packet. */ do { - i =3D ring->cur; idx =3D ring->slot[i].buf_idx; morefrag =3D (ring->slot[i].flags & NS_MOREFRAG); - s->iov[iovcnt].iov_base =3D (u_char *)NETMAP_BUF(ring, idx); + s->iov[iovcnt].iov_base =3D (void *)NETMAP_BUF(ring, idx); s->iov[iovcnt].iov_len =3D ring->slot[i].len; iovcnt++; + i =3D nm_ring_next(ring, i); + } while (i !=3D tail && morefrag); =20 - ring->cur =3D ring->head =3D nm_ring_next(ring, i); - } while (!nm_ring_empty(ring) && morefrag); + /* Advance ring->cur to tell the kernel that we have seen the slot= s. */ + ring->cur =3D i; =20 - 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 releasin= g the + * incomplete slots by updating ring->head. We will hopefully + * re-read the complete packet the next time we are called. */ + break; } =20 iovsize =3D qemu_sendv_packet_async(&s->nc, s->iov, iovcnt, netmap_send_completed); =20 + /* Release the slots to the kernel. */ + ring->head =3D i; + if (iovsize =3D=3D 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; } --=20 2.5.0