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,URIBL_BLOCKED,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 A0245C76191 for ; Mon, 15 Jul 2019 14:47:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 74FDA2067C for ; Mon, 15 Jul 2019 14:47:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563202062; bh=rU3Ez2wWMrrE/iar+jy6anGCgLmCwgHT+Bint4y05vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=FWj9q2ho4Aje6w9NB06Sje7q1c/vVj17pR6EQjSmHdM7r4n/IDt+h0Sm0vrWluj57 vzt2k7AMX/kYa1dMyodmFTJjTQxbMPDb0eBzjDUWZrm9zCbMJcGNrzMh0CxX9YT+Kc PFOveIQDHRjIkvpDPv3gvxJRE+GRgbOw8ABo2iSM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405207AbfGOOrh (ORCPT ); Mon, 15 Jul 2019 10:47:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:42380 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405195AbfGOOre (ORCPT ); Mon, 15 Jul 2019 10:47:34 -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 6F8D621530; Mon, 15 Jul 2019 14:47:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563202053; bh=rU3Ez2wWMrrE/iar+jy6anGCgLmCwgHT+Bint4y05vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OVyJ3iXksY9MVgxHgc0hcVaBiwsCjF5g0imSXYrjQubrpe79iNi2OV5WJxf6RBBrn PVch88OIUWEnKOssvz57aiaCWzAMv8Dql3R5EnLPlbDsx22yVyZeYW1Hu44+JtEz3p iQIUdcvXoNg/ubbq3ehj2SLY29A9AkTU8gJzEowo= 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 4.4 33/53] vhost_net: disable zerocopy by default Date: Mon, 15 Jul 2019 10:45:15 -0400 Message-Id: <20190715144535.11636-33-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715144535.11636-1-sashal@kernel.org> References: <20190715144535.11636-1-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 645b2197930e..f46317135224 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -30,7 +30,7 @@ #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