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 2062CC76191 for ; Mon, 15 Jul 2019 14:22:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E1664217F4 for ; Mon, 15 Jul 2019 14:22:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200579; bh=3naJwCoZa8U1fnAU2ndnwcAG/epwsikMi3505JUZVV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vTW1IBXZvQd1EZ91JFj0/+NiMNnsg29LcJK2kVHZWDTblTEuA29wJxWKSCt/Cc7pk UffTfsV9KV8TFWPfq2TCjHJSmSmn8K+j+oeSaVvbumHULZw/XyWm6ur4t4sM90kcLr c0bS4bC58lrcY+GGulkTXYkoRpTwi0Xe/Cdh3ou0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390090AbfGOOWr (ORCPT ); Mon, 15 Jul 2019 10:22:47 -0400 Received: from mail.kernel.org ([198.145.29.99]:52048 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390619AbfGOOWq (ORCPT ); Mon, 15 Jul 2019 10:22:46 -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 3FA8A2184E; Mon, 15 Jul 2019 14:22:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200565; bh=3naJwCoZa8U1fnAU2ndnwcAG/epwsikMi3505JUZVV8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rh7AIdSwPhTm0xzmkndySVeaHA/5g85v0DBZoGwbLuoAh+0UML/B7/AkKR05oETsM qjYRwBnbKBQrcpgc6DPim2bHIRJfBUPy8oPF427QTYWUW6bvUE40q2uQyITclN2bdK 7FK06otblGb9T7WdTooefkzlP8qMZioJ3TfgjzH8= 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 4.19 079/158] vhost_net: disable zerocopy by default Date: Mon, 15 Jul 2019 10:16:50 -0400 Message-Id: <20190715141809.8445-79-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715141809.8445-1-sashal@kernel.org> References: <20190715141809.8445-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 39155d7cc894..ae704658b528 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