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=unavailable 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 1EAFBC32750 for ; Fri, 2 Aug 2019 10:03:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED9162086A for ; Fri, 2 Aug 2019 10:03:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564740196; bh=BhjJmWsPWXbSRj2VJ9rEfGZ74XRLKw1Y3CmhvhAgwbk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=EeXXjCX1FHvGngqZ8o9p4D6ryfs9VLCkcYsbzPxdDyzhtg8xGM5eFIhgASuQDAzlV pFzxqQDNH4hVNOR0J8gACnuZsgkSDxE7UkI43e0Yj/fgC3F7nMu6Op8xpwb7fK1aoD f5RuDj8s3PV7OGrn6zQD3O2xYK9a0jysFIrab5Cg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405909AbfHBKDL (ORCPT ); Fri, 2 Aug 2019 06:03:11 -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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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