From patchwork Fri Mar 2 18:57:51 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 144310 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 62D1CB6EF1 for ; Sat, 3 Mar 2012 05:59:12 +1100 (EST) Received: from localhost ([::1]:45907 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S3Xh8-0006cW-9o for incoming@patchwork.ozlabs.org; Fri, 02 Mar 2012 13:59:10 -0500 Received: from eggs.gnu.org ([208.118.235.92]:56417) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S3Xgd-0005Tu-QA for qemu-devel@nongnu.org; Fri, 02 Mar 2012 13:58:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1S3XgO-0003xM-3L for qemu-devel@nongnu.org; Fri, 02 Mar 2012 13:58:39 -0500 Received: from david.siemens.de ([192.35.17.14]:32729) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1S3XgN-0003wq-Ph for qemu-devel@nongnu.org; Fri, 02 Mar 2012 13:58:24 -0500 Received: from mail1.siemens.de (localhost [127.0.0.1]) by david.siemens.de (8.13.6/8.13.6) with ESMTP id q22Ivuob008342; Fri, 2 Mar 2012 19:57:56 +0100 Received: from mchn199C.mchp.siemens.de ([139.25.109.49]) by mail1.siemens.de (8.13.6/8.13.6) with ESMTP id q22IvrFS000793; Fri, 2 Mar 2012 19:57:56 +0100 From: Jan Kiszka To: qemu-devel@nongnu.org Date: Fri, 2 Mar 2012 19:57:51 +0100 Message-Id: <470be314087573ea677d3d70c75eaacc241c9b07.1330714672.git.jan.kiszka@siemens.com> X-Mailer: git-send-email 1.7.3.4 In-Reply-To: References: In-Reply-To: References: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 192.35.17.14 Cc: Stefan Weil , Zhi Yong Wu , Fabien Chouteau Subject: [Qemu-devel] [PATCH v2 2/4] slirp: Fix queue walking in if_start X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Another attempt to get this right: We need to carefully walk both the fastq and the batchq in if_start while trying to send packets to possibly not yet resolved hosts on the virtual network. So far we just requeued a delayed packet where it was and then started walking the queues from the top again - that couldn't work. Now we pre- calculate the next packet in the queue so that the current one can safely be removed if it was sent successfully. We also need to take into account that the next packet can be from the same session if the current one was sent and there are no other sessions. CC: Fabien Chouteau CC: Zhi Yong Wu CC: Stefan Weil Signed-off-by: Jan Kiszka --- slirp/if.c | 46 +++++++++++++++++++++++++++------------------- 1 files changed, 27 insertions(+), 19 deletions(-) diff --git a/slirp/if.c b/slirp/if.c index 14fdef1..6f59620 100644 --- a/slirp/if.c +++ b/slirp/if.c @@ -158,26 +158,35 @@ void if_start(Slirp *slirp) { uint64_t now = qemu_get_clock_ns(rt_clock); int requeued = 0; - bool from_batchq = false; - struct mbuf *ifm, *ifqt; + struct mbuf *ifm, *ifm_next, *ifqt; DEBUG_CALL("if_start"); - while (slirp->if_queued) { + if (slirp->if_fastq.ifq_next != &slirp->if_fastq) { + ifm_next = slirp->if_fastq.ifq_next; + } else if (slirp->next_m != &slirp->if_batchq) { + /* Nothing on fastq, pick up from batchq via next_m */ + ifm_next = slirp->next_m; + } else { + ifm_next = NULL; + } + + while (ifm_next) { /* check if we can really output */ - if (!slirp_can_output(slirp->opaque)) + if (!slirp_can_output(slirp->opaque)) { return; + } - /* - * See which queue to get next packet from - * If there's something in the fastq, select it immediately - */ - if (slirp->if_fastq.ifq_next != &slirp->if_fastq) { - ifm = slirp->if_fastq.ifq_next; - } else { - /* Nothing on fastq, pick up from batchq via next_m */ - ifm = slirp->next_m; - from_batchq = true; + ifm = ifm_next; + + ifm_next = ifm->ifq_next; + if (ifm_next == &slirp->if_fastq) { + /* No more packets in fastq, switch to batchq */ + ifm_next = slirp->next_m; + } + if (ifm_next == &slirp->if_batchq) { + /* end of batchq */ + ifm_next = NULL; } slirp->if_queued--; @@ -189,7 +198,7 @@ void if_start(Slirp *slirp) continue; } - if (from_batchq) { + if (ifm == slirp->next_m) { /* Set which packet to send on next iteration */ slirp->next_m = ifm->ifq_next; } @@ -202,11 +211,11 @@ void if_start(Slirp *slirp) if (ifm->ifs_next != ifm) { insque(ifm->ifs_next, ifqt); ifs_remque(ifm); - /* Set next_m if the session packet is now the only one on - * batchq */ + /* Set next_m and ifm_next if the session packet is now the only + * one on batchq */ if (ifqt == &slirp->if_batchq && slirp->next_m == &slirp->if_batchq) { - slirp->next_m = ifm->ifs_next; + slirp->next_m = ifm_next = ifm->ifs_next; } } @@ -217,7 +226,6 @@ void if_start(Slirp *slirp) } m_free(ifm); - } slirp->if_queued = requeued;