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 1EED4C76186 for ; Wed, 24 Jul 2019 19:48:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D9EBE214AF for ; Wed, 24 Jul 2019 19:48:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563997691; bh=gz2H/pXpGaEFJ3NWwbUY2T7vre0nwdVuho6rGUaJPes=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=SAMFwksY3iJAgZMIeQQFIpGKVEHBy/WRv365PIB58gnO7x/oU6rJb07qpOUKtwfSe J0z5jEdDHjTk3DtLSN28RpJFW+osz5z1Y94tVlYFjZgKiH3qbSh9eG+O9k5plZDnck 0rnUr3rhGA6Idtr/Kf2XYBbD/JaE41CvFL5Zrgww= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390438AbfGXTsJ (ORCPT ); Wed, 24 Jul 2019 15:48:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:55192 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391351AbfGXTsG (ORCPT ); Wed, 24 Jul 2019 15:48:06 -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 61077214AF; Wed, 24 Jul 2019 19:48:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563997685; bh=gz2H/pXpGaEFJ3NWwbUY2T7vre0nwdVuho6rGUaJPes=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M/y8bgWJXMcSqK1J9Sk5pZRqVqAk1aPqewVeq7LEt4fpd9LRCGpLjd5Up0XFmN7RP FT0Osu6+gqauGmI5hpwgO2AIBlgZaqdg4UczONoYHYgXgyTAD1VYJ4KC7CjJN0/Pzv WTtlI/jSX2BFgdGHMjqzslWYMI5QWLAig1IgO9zU= 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 5.1 107/371] vhost_net: disable zerocopy by default Date: Wed, 24 Jul 2019 21:17:39 +0200 Message-Id: <20190724191732.899609057@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190724191724.382593077@linuxfoundation.org> References: <20190724191724.382593077@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 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