From patchwork Fri Feb 15 08:27:18 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 220679 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 B35C72C007A for ; Fri, 15 Feb 2013 19:27:35 +1100 (EST) Received: from localhost ([::1]:39311 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U6Gdp-00079N-9q for incoming@patchwork.ozlabs.org; Fri, 15 Feb 2013 03:27:33 -0500 Received: from eggs.gnu.org ([208.118.235.92]:52252) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U6Gdc-00079G-1R for qemu-devel@nongnu.org; Fri, 15 Feb 2013 03:27:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U6GdW-0004mp-8K for qemu-devel@nongnu.org; Fri, 15 Feb 2013 03:27:19 -0500 Received: from ssl.dlhnet.de ([91.198.192.8]:47380 helo=ssl.dlh.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U6GdW-0004mf-2M for qemu-devel@nongnu.org; Fri, 15 Feb 2013 03:27:14 -0500 Received: from localhost (localhost [127.0.0.1]) by ssl.dlh.net (Postfix) with ESMTP id 553D314D6B0; Fri, 15 Feb 2013 09:27:12 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at ssl.dlh.net Received: from ssl.dlh.net ([127.0.0.1]) by localhost (ssl.dlh.net [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pGofKX9HILYW; Fri, 15 Feb 2013 09:27:11 +0100 (CET) Received: from [172.21.12.60] (unknown [82.141.1.226]) by ssl.dlh.net (Postfix) with ESMTPSA id B9AAD14D46A; Fri, 15 Feb 2013 09:27:11 +0100 (CET) Message-ID: <511DF166.2070105@dlhnet.de> Date: Fri, 15 Feb 2013 09:27:18 +0100 From: Peter Lieven User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: qemu-devel@nongnu.org References: <20121123110146.GC7051@redhat.com> <50FE5607.9020405@dlhnet.de> <20130123100312.GA8108@redhat.com> <5119E9DC.3000505@dlhnet.de> <20130212090850.GB22029@redhat.com> <056542E4-18E4-4C9F-AC96-60661768D6AF@dlhnet.de> <511A0DBB.7080907@msgid.tls.msk.ru> <20130212095422.GA23270@redhat.com> <20130212104331.GA23495@redhat.com> In-Reply-To: <20130212104331.GA23495@redhat.com> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 91.198.192.8 Cc: Stefan Hajnoczi , Michael Tokarev , "Michael S. Tsirkin" Subject: [Qemu-devel] [PATCH] tap: set IFF_ONE_QUEUE per default 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 historically the kernel queues packets two times. once at the device and second in qdisc. this is believed to cause interface stalls if one of these queues overruns. setting IFF_ONE_QUEUE is the default in kernels >= 3.8. the flag is ignored since then. see kernel commit 5d097109257c03a71845729f8db6b5770c4bbedc Signed-off-by: Peter Lieven Reviewed-by: Stefan Hajnoczi --- net/tap-linux.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/tap-linux.c b/net/tap-linux.c index a953189..2759b78 100644 --- a/net/tap-linux.c +++ b/net/tap-linux.c @@ -49,7 +49,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, return -1; } memset(&ifr, 0, sizeof(ifr)); - ifr.ifr_flags = IFF_TAP | IFF_NO_PI; + ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE; if (*vnet_hdr) { unsigned int features;