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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 BD2BFC433FF for ; Fri, 2 Aug 2019 10:03:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 896B42067D for ; Fri, 2 Aug 2019 10:03:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564740193; bh=BhjJmWsPWXbSRj2VJ9rEfGZ74XRLKw1Y3CmhvhAgwbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=k+pkEh0vkhhA+rst3qpmvrW9T2ipa/k0ELkqdiKzOsoSGBYh3Jxe6fF94vY7A05dn Mouoj67wpuypxfIx+cXTbHR8xbiXjlq6Q816ydTcf8cJ3NjLzT/mdnkODvIMX3N/mF RQFVKvGcDtb2Afz5RvANLe0RK+KZ5ItR7u157bzU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407168AbfHBKDM (ORCPT ); Fri, 2 Aug 2019 06:03:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:43678 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404895AbfHBJls (ORCPT ); Fri, 2 Aug 2019 05:41:48 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 63F0D20B7C; Fri, 2 Aug 2019 09:41:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564738907; bh=BhjJmWsPWXbSRj2VJ9rEfGZ74XRLKw1Y3CmhvhAgwbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rjtvzupNjNIfNkR7QbM1RpTRzggagUL6R/zJDNxWrevr787uEdBcM/y13Qh29YsVO sx/+YjtKjO2HwtaOZMDIqNdVCHl+NlfQIDSS3mFBFBenwSoaHWNPNvryb++oXpsQDQ QQtdrnZJ6Mtq286xp2qWj6vcVpaabQZUOA61ZmYY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jason Wang , "Michael S. Tsirkin" , "David S. Miller" , Sasha Levin Subject: [PATCH 4.9 042/223] vhost_net: disable zerocopy by default Date: Fri, 2 Aug 2019 11:34:27 +0200 Message-Id: <20190802092241.708015732@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092238.692035242@linuxfoundation.org> References: <20190802092238.692035242@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ 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 681d0eade82f..75e1089dfb01 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