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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 A4240C5518C for ; Wed, 22 Apr 2020 10:50:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8336D2073A for ; Wed, 22 Apr 2020 10:50:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587552611; bh=1247amiGWYj46GQXVS7haaALg3Qs/29K8ODPpL1H2dI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=P8QdiZ00cUeLUWsf+dSX9E210zWA2TDg0EZ/Hl35iI04BJXtphSzH1zwNrNeaO5qR qW7jUe+K3a1IxUIOEq5op2v3uPvZB5orey1cBmYRAFTwBxpIt/D1T8mvX5jLx1rWhl Gw3gW8YRrqcwBJmXsxFiiB2qx9rVOiIVtFdd2vIc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729359AbgDVKMq (ORCPT ); Wed, 22 Apr 2020 06:12:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:45570 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729340AbgDVKM3 (ORCPT ); Wed, 22 Apr 2020 06:12:29 -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 C0AD620575; Wed, 22 Apr 2020 10:12:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587550349; bh=1247amiGWYj46GQXVS7haaALg3Qs/29K8ODPpL1H2dI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SydP2LD5GweYO0582ewFHQqD2n2U0ImlKOZjjPnEkQOzixB41g2/FLK+tOIogKXXP YZN7zeKsQcZiKi7KUHsioFYpw8TX56yvwDbf4jtkJwMF/ZoixIbfYyg5Vk6i83A3QU 6sR7TN+pZ3el9rW1IRs6EMa2/BDdxq7h2Sr0u9iA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dmitry Yakunin , Konstantin Khlebnikov , "David S. Miller" Subject: [PATCH 4.14 111/199] net: revert default NAPI poll timeout to 2 jiffies Date: Wed, 22 Apr 2020 11:57:17 +0200 Message-Id: <20200422095108.781018091@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200422095057.806111593@linuxfoundation.org> References: <20200422095057.806111593@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 From: Konstantin Khlebnikov [ Upstream commit a4837980fd9fa4c70a821d11831698901baef56b ] For HZ < 1000 timeout 2000us rounds up to 1 jiffy but expires randomly because next timer interrupt could come shortly after starting softirq. For commonly used CONFIG_HZ=1000 nothing changes. Fixes: 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") Reported-by: Dmitry Yakunin Signed-off-by: Konstantin Khlebnikov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3575,7 +3575,8 @@ EXPORT_SYMBOL(netdev_max_backlog); int netdev_tstamp_prequeue __read_mostly = 1; int netdev_budget __read_mostly = 300; -unsigned int __read_mostly netdev_budget_usecs = 2000; +/* Must be at least 2 jiffes to guarantee 1 jiffy timeout */ +unsigned int __read_mostly netdev_budget_usecs = 2 * USEC_PER_SEC / HZ; int weight_p __read_mostly = 64; /* old backlog weight */ int dev_weight_rx_bias __read_mostly = 1; /* bias for backlog weight */ int dev_weight_tx_bias __read_mostly = 1; /* bias for output_queue quota */