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 3028FC7618F for ; Mon, 15 Jul 2019 14:09:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 09280206B8 for ; Mon, 15 Jul 2019 14:09:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563199794; bh=QMd19WpKGYJalQzYk9IGJ+zHV5kW5Qk/do8V4oNjR8o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=W/L2q2/QlkDkw062V8YIMlS60EqmL+0Lw81xDsOlxZgSiaCX5VSXmDLplYZxYqHHX xdmcRe8amvEIrwOhUtB7mgVYrwE1EVe7Ag79DmIoQaK+6TTxUHM9SZtDcbTyStnTqW e2SODitkb89POzlVygmxsSA6VNmUqXlYYxDCOGPU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731030AbfGOOJx (ORCPT ); Mon, 15 Jul 2019 10:09:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:33764 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388737AbfGOOJq (ORCPT ); Mon, 15 Jul 2019 10:09:46 -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 7640F21530; Mon, 15 Jul 2019 14:09:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563199786; bh=QMd19WpKGYJalQzYk9IGJ+zHV5kW5Qk/do8V4oNjR8o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aNufNuNDFSMawH6WIhTl/zIQtQ/zNbNr+VCIzSA3gFE4lKKEp6E6MAvT6A2YYLpyI ufVk+4DqGTUTM8v7GYWCpJ9otE62CcoXaQi75zwuH2UyQemPtvLfauaijUHy2A0xmX Oeqq0oynuH9/TAMSut9lPAf4s/8/DgDlpHnUe+Sk= 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 5.1 105/219] vhost_net: disable zerocopy by default Date: Mon, 15 Jul 2019 10:01:46 -0400 Message-Id: <20190715140341.6443-105-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715140341.6443-1-sashal@kernel.org> References: <20190715140341.6443-1-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 df51a35cf537..8beacbee2553 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -36,7 +36,7 @@ #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