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,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 CD95DC76191 for ; Mon, 15 Jul 2019 13:54:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9A0BC2081C for ; Mon, 15 Jul 2019 13:54:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563198856; bh=5+J+JiR3UfcDNjQLIXc45plyT84o2HFsh9ByO2Sil/Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qskKacZ1UvaonJPy1nFIbl8X7x/Zt6f320OQPTBS89waXR3w7IPrc/O8qI3Cib2l+ /eDXNtv9bZt3tHNUoh7dWj7VI6G7Ea8rbgGiw5c1proyVLike0SVCLR7nMuvN8fNHv uWReiexj/Ve3DN92mBHfDlfGqV6zpS2FoAKr82j8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730496AbfGONyP (ORCPT ); Mon, 15 Jul 2019 09:54:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:53492 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731811AbfGONyN (ORCPT ); Mon, 15 Jul 2019 09:54:13 -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 F0E73206B8; Mon, 15 Jul 2019 13:54:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563198853; bh=5+J+JiR3UfcDNjQLIXc45plyT84o2HFsh9ByO2Sil/Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i8xM8Pmew9a+AmgVZvNgv/TzIG6xaxAqoTYDPopj4eCsCZzxY+A0nE7tRVUFTj54P e6zzosWvJcOb8T6+MEMLTbHnrQ4EFL1NWxZypBuZYRk4RQoYM/MfuKKTiq2BeDkhI1 IacKhBxLkLqRuF31uq/iea/OlEavfPu9iXALn6R4= 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 5.2 119/249] vhost_net: disable zerocopy by default Date: Mon, 15 Jul 2019 09:44:44 -0400 Message-Id: <20190715134655.4076-119-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715134655.4076-1-sashal@kernel.org> References: <20190715134655.4076-1-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 d57ebdd616d9..247e5585af5d 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