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=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 E1242C7618F for ; Mon, 15 Jul 2019 14:42:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AA287205ED for ; Mon, 15 Jul 2019 14:42:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201777; bh=FSZoq9WrIW60R8uTCwm1dsGcg3a3pKKxZCGZIwUgr7E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=MTHb0Y6+4P6F8WTFw3Wixyx4cZ1QLNBeOfMl1RBarmNTtUtZyolQp1npUcvzx8hAD k8n4NDzRwGUkcOVmr03O3t/FjqHVp01XiMIv6mqqeF4MotLRMKc9HIom1ZqWmkKaBt tADDUoGFFDwHOCo1vgBEHs/ZDrLPz+sTmOCzSgzw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404217AbfGOOjR (ORCPT ); Mon, 15 Jul 2019 10:39:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:38578 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391901AbfGOOjQ (ORCPT ); Mon, 15 Jul 2019 10:39:16 -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 7188A2086C; Mon, 15 Jul 2019 14:39:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201555; bh=FSZoq9WrIW60R8uTCwm1dsGcg3a3pKKxZCGZIwUgr7E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LL1unzeYM9KVRkaJcDd/Co61vjByfDxzd/4O4kTth3nYe7Pm41b/CoYEqKT4QygAD jySGWVNy46OVejwDCME/pYC6FhXN0FSV1yT0L1hZpfSrPVhS/x96GXWsuR5ph0l5EV d3aKto+D+heEIToiC/Y20yPhnd1HGKXH6slFO65M= 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 4.9 41/73] vhost_net: disable zerocopy by default Date: Mon, 15 Jul 2019 10:35:57 -0400 Message-Id: <20190715143629.10893-41-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715143629.10893-1-sashal@kernel.org> References: <20190715143629.10893-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@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 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