From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 063F0C7618F for ; Mon, 15 Jul 2019 14:32:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D054B212F5 for ; Mon, 15 Jul 2019 14:32:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201123; bh=EtiFc2T+Mq1gjzX5kCGjj/L1KO5/UuT62CT4bPQlvu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=fT69oMNugHQPgR7XZZsd37yq0kf6nkM7r1e2ayt9tegALyJobTMLsAyiv/Z6JuNsn Rj1kFvmEBC96HX0/H+QyrpCZxfF6fVuoY0GcKnFC/FxzgNsVdged0h3HX+k0VcbgXc TXqcr/VybEzR4n4jPZ2MEbLLvLB8SviRgq45Gp54= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403996AbfGOOcC (ORCPT ); Mon, 15 Jul 2019 10:32:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:46580 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391810AbfGOOcA (ORCPT ); Mon, 15 Jul 2019 10:32:00 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 83EDF21849; Mon, 15 Jul 2019 14:31:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201119; bh=EtiFc2T+Mq1gjzX5kCGjj/L1KO5/UuT62CT4bPQlvu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Wu1tY5TTMunFKA5odcXMPT8v7xculkcTFW1fD+Zs7G1L7VJsB1GA59SIpLNh9rp/X hwtedRwJKebkn+9MuN1Mk2MkvQuq0O+ik6gumqe5sLdm7WovPIGtEAw/W1Y9OumCtA XAISXhB4ujiECTvsQyM+6MwfIUsVqLv6IPQ7fuBk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jason Wang , "Michael S . Tsirkin" , "David S . Miller" , Sasha Levin , kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 056/105] vhost_net: disable zerocopy by default Date: Mon, 15 Jul 2019 10:27:50 -0400 Message-Id: <20190715142839.9896-56-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715142839.9896-1-sashal@kernel.org> References: <20190715142839.9896-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jason Wang [ Upstream commit 098eadce3c622c07b328d0a43dda379b38cf7c5e ] Vhost_net was known to suffer from HOL[1] issues which is not easy to fix. Several downstream disable the feature by default. What's more, the datapath was split and datacopy path got the support of batching and XDP support recently which makes it faster than zerocopy part for small packets transmission. It looks to me that disable zerocopy by default is more appropriate. It cold be enabled by default again in the future if we fix the above issues. [1] https://patchwork.kernel.org/patch/3787671/ Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/vhost/net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index b40e8ded49c6..4d11152e60c1 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -35,7 +35,7 @@ #include "vhost.h" -static int experimental_zcopytx = 1; +static int experimental_zcopytx = 0; module_param(experimental_zcopytx, int, 0444); MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" " 1 -Enable; 0 - Disable"); -- 2.20.1 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 4.14 056/105] vhost_net: disable zerocopy by default Date: Mon, 15 Jul 2019 10:27:50 -0400 Message-ID: <20190715142839.9896-56-sashal@kernel.org> References: <20190715142839.9896-1-sashal@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190715142839.9896-1-sashal@kernel.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sasha Levin , kvm@vger.kernel.org, "Michael S . Tsirkin" , netdev@vger.kernel.org, virtualization@lists.linux-foundation.org, "David S . Miller" List-Id: virtualization@lists.linuxfoundation.org From: Jason Wang [ Upstream commit 098eadce3c622c07b328d0a43dda379b38cf7c5e ] Vhost_net was known to suffer from HOL[1] issues which is not easy to fix. Several downstream disable the feature by default. What's more, the datapath was split and datacopy path got the support of batching and XDP support recently which makes it faster than zerocopy part for small packets transmission. It looks to me that disable zerocopy by default is more appropriate. It cold be enabled by default again in the future if we fix the above issues. [1] https://patchwork.kernel.org/patch/3787671/ Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/vhost/net.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index b40e8ded49c6..4d11152e60c1 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -35,7 +35,7 @@ #include "vhost.h" -static int experimental_zcopytx = 1; +static int experimental_zcopytx = 0; module_param(experimental_zcopytx, int, 0444); MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" " 1 -Enable; 0 - Disable"); -- 2.20.1