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 2B97FC433FF for ; Mon, 29 Jul 2019 20:14:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EA02D205F4 for ; Mon, 29 Jul 2019 20:14:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564431243; bh=wK7b6COeD7dL3yqszsDzRkPT8M+NtPOZ+usPFbJcXvs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=nFL+hebmDWq0+Ez9XhLFfNdeIUqSziESt8RJSnki46yP4fH0IiBkVLxnxDEWkWO+m /gT1jsqAVlAf9WCJn3LqqGwiikxOuARgSgZns619qeCaTJ4glOwJ64rUKj6MHFuivF Y7Eig3/FOJLTD5rGO0xhuYNNrMEBJpIVaZKvAmOA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729127AbfG2T26 (ORCPT ); Mon, 29 Jul 2019 15:28:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:41608 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727564AbfG2T2x (ORCPT ); Mon, 29 Jul 2019 15:28:53 -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 22C692070B; Mon, 29 Jul 2019 19:28:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428532; bh=wK7b6COeD7dL3yqszsDzRkPT8M+NtPOZ+usPFbJcXvs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QEk4dfNT2LOBs2CGwzTFq2SucBWmLlVzRJ/Sit8IapDl3cyVE7yUQwTEUOnuuG/0c ccC2vzqbB7/wIy0rTmrWx/ubmNRhBlNOkx4/PUhCqLKy6ynmry9cv7K3jUxh2zdRyB Mrynq+iTXzuCD6RzsJdEAgPnHDOIq/T4kUkQoPVM= 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 4.14 057/293] vhost_net: disable zerocopy by default Date: Mon, 29 Jul 2019 21:19:08 +0200 Message-Id: <20190729190828.485573190@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190820.321094988@linuxfoundation.org> References: <20190729190820.321094988@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 b40e8ded49c6..4d11152e60c1 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -35,7 +35,7 @@ #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