From patchwork Mon May 7 19:30:12 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Erwan Velu X-Patchwork-Id: 157387 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id B566DB6FA8 for ; Tue, 8 May 2012 05:30:41 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757320Ab2EGTaS (ORCPT ); Mon, 7 May 2012 15:30:18 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:38850 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753964Ab2EGTaR (ORCPT ); Mon, 7 May 2012 15:30:17 -0400 Received: by eeit10 with SMTP id t10so90210eei.19 for ; Mon, 07 May 2012 12:30:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :content-type:content-transfer-encoding; bh=lpbDrQoCBfkM0nEysyRvhnrPxE4G7JCRFASRG8GQKco=; b=sKsFbjHyhQr8sAvu7/bHzFAqYlUhvefzeR0N9CwGcaUCbLj3uMuNnR5gZ7GLr8330I Ol4mzZ5y7tYwFVAwSJUpYokeMDA1v+hUP9etKexaWgyl6HqidVR6tIZ4OaxW/cbS3rMf zAHr2PSv9qlsTZPekx19OF1gA3BH4ITqVMjLvQigE1Mv+Kzs8AgDH+DPhktuFdm+RAsL XH0OCKu7eej41MjMS81GFeoay/NmP2BmfpVDZheqyyp0DBypFlpHShWGjZ6ugk+Ypi6F SX+e3Du9awqVXI12sWY8HqdRjrxqq1/MMRx4rAXUEdWJrq5WV/ek7dbZ9u+8wS876/e6 XWnQ== Received: by 10.14.39.137 with SMTP id d9mr2931124eeb.57.1336419016131; Mon, 07 May 2012 12:30:16 -0700 (PDT) Received: from localhost.localdomain (lns-bzn-48f-62-147-157-222.adsl.proxad.net. [62.147.157.222]) by mx.google.com with ESMTPS id m42sm90845270eef.0.2012.05.07.12.30.13 (version=SSLv3 cipher=OTHER); Mon, 07 May 2012 12:30:14 -0700 (PDT) Message-ID: <4FA822C4.60809@gmail.com> Date: Mon, 07 May 2012 21:30:12 +0200 From: Erwan Velu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.4) Gecko/20120426 Thunderbird/10.0.4 MIME-Version: 1.0 To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org CC: tshimizu818@gmail.com Subject: [PATCH] pch_gbe: Adding read memory barriers Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From bb1e271db0fa1a29df19bede69faf8004389132d Mon Sep 17 00:00:00 2001 From: Erwan Velu Date: Mon, 7 May 2012 19:15:29 +0000 Subject: [PATCH 1/1] pch_gbe: Adding read memory barriers Under a strong incoming packet stream and/or high cpu usage, the pch_gbe driver reports "Receive CRC Error" and discards packet. It occurred on an Intel ATOM E620T while running a 300mbit/sec multicast network stream leading to a ~100% cpu usage. Adding rmb() calls before considering the network card's status solve this issue. Getting it into stable would be perfect as it solves reliability issues. Signed-off-by: Erwan Velu --- .../net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c index 8035e5f..ace3654 100644 --- a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c +++ b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c @@ -1413,6 +1413,7 @@ static irqreturn_t pch_gbe_intr(int irq, void *data) pch_gbe_mac_set_pause_packet(hw); } } + smp_rmb(); /* prevent any other reads before*/ /* When request status is Receive interruption */ if ((int_st & (PCH_GBE_INT_RX_DMA_CMPLT | PCH_GBE_INT_TX_CMPLT)) || @@ -1582,6 +1584,7 @@ pch_gbe_clean_tx(struct pch_gbe_adapter *adapter, i = tx_ring->next_to_clean; tx_desc = PCH_GBE_TX_DESC(*tx_ring, i); + rmb(); /* prevent any other reads before*/ pr_debug("gbec_status:0x%04x dma_status:0x%04x\n", tx_desc->gbec_status, tx_desc->dma_status); @@ -1682,6 +1685,7 @@ pch_gbe_clean_rx(struct pch_gbe_adapter *adapter, while (*work_done < work_to_do) { /* Check Rx descriptor status */ rx_desc = PCH_GBE_RX_DESC(*rx_ring, i); + rmb(); /* prevent any other reads before*/ if (rx_desc->gbec_status == DSC_INIT16) break; cleaned = true;