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=-8.6 required=3.0 tests=DATE_IN_PAST_06_12, 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 5E0D8C7618B for ; Thu, 25 Jul 2019 05:53:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2AA7F21850 for ; Thu, 25 Jul 2019 05:53:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564034018; bh=zH0OPT1fvPg9KVf3AJA47iF403EQgtr6HZTBNzn0//o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kjxrsNGwUgO/xOZdMCI1hUyIHslpkH3aAtIFHmOlm3HJg88Rs3I6ScpMAy7O/rooc j2GhZOsk7NOgM8hegBDTdRIEJQXMigiSxo7B0SDhj98E6iriZaC8DlkdKNzW+U6np5 zIhJaLmzeRQtiTQG2fWFH09nzMrNLd5AeCYubtyc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403975AbfGYFjH (ORCPT ); Thu, 25 Jul 2019 01:39:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:53262 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403967AbfGYFjH (ORCPT ); Thu, 25 Jul 2019 01:39:07 -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 04EB322C7B; Thu, 25 Jul 2019 05:39:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564033146; bh=zH0OPT1fvPg9KVf3AJA47iF403EQgtr6HZTBNzn0//o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2dZlolshFnrPJAtOiUP9Hc50pMp70N8RJxcE1eY7tNP01q57W3HjjgHWHmlQ4u89e 6wQh9DUcjdLwTzLBUtg05UHH7dxZrUj0gvHe2qa0n/WSOdwgzZrSYBNbtiLhWv1LOg E5PfIcRGmkAtaRdiWWySPJVGPVkZ59EEYRCoaBXo= 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 4.19 081/271] vhost_net: disable zerocopy by default Date: Wed, 24 Jul 2019 21:19:10 +0200 Message-Id: <20190724191702.128646931@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190724191655.268628197@linuxfoundation.org> References: <20190724191655.268628197@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 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