From patchwork Tue Mar 20 02:42:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 10296057 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8A22B602C2 for ; Tue, 20 Mar 2018 02:49:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 785B428DA8 for ; Tue, 20 Mar 2018 02:49:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6D0B428E21; Tue, 20 Mar 2018 02:49:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7CD6C28E21 for ; Tue, 20 Mar 2018 02:49:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=lS0V3+iQnioonwez6B/+aC+CKs4MwbvXQzoOmaJb8yg=; b=i98XGspIF5vDsa DbfgEy8Z1FA37K9CRkUAFBky/zfbY1oYUWnMeKDhwLwOMoRCFnYO1DPcYq/jXN/BlPXjBIG7htIV9 Mdsj2fxqySUfTAPMUKsNlJMQPPZ8ybWYOTYJuheim7UjSM5y/x3ZukVMDV024s+7KxsS/8kJBsYn5 oQP6/PTWPWp7n5IsniBXkmAS3CRc+klxZGBSn5/AB9RfmeFhJgy4oR09XTj7c0aG6SsTo5uN27Jc4 VlL1WPT4JQ32rxz3ly8XyOSIbyrz8hFDJzhQnmPCBs8o/3IO/eJqukqu9CvLwzU3lv7WHo0L+gQ3c ZPNytzZohIbEAUMgUXJA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1ey7Kl-0005Cv-K9; Tue, 20 Mar 2018 02:49:07 +0000 Received: from smtp.codeaurora.org ([198.145.29.96]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1ey7Eg-0008Tb-7Q for linux-arm-kernel@lists.infradead.org; Tue, 20 Mar 2018 02:42:53 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id CED8860C54; Tue, 20 Mar 2018 02:42:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521513762; bh=BlzNrv3XIINk094zTki72LiSESAYjvgRuP09amGJ4UY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BZg5UhyBX/flXYX4riP2jdcs7zoF0IX5YLavV65R7P8zHw/S8HBRuMZhmKFuE/z5f wqGs+buLY3qXkDeGjO6eg7k0ELd+HpXX6/hEymUsBU877jthHOXONGE4ZgbqXBtheZ 3ngytcmMXIL+F4hsqOHCaqyF2Pg/uK9sjUy9XoJg= Received: from drakthul.qualcomm.com (global_nat1_iad_fw.qualcomm.com [129.46.232.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: okaya@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 550DA60C67; Tue, 20 Mar 2018 02:42:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521513762; bh=BlzNrv3XIINk094zTki72LiSESAYjvgRuP09amGJ4UY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BZg5UhyBX/flXYX4riP2jdcs7zoF0IX5YLavV65R7P8zHw/S8HBRuMZhmKFuE/z5f wqGs+buLY3qXkDeGjO6eg7k0ELd+HpXX6/hEymUsBU877jthHOXONGE4ZgbqXBtheZ 3ngytcmMXIL+F4hsqOHCaqyF2Pg/uK9sjUy9XoJg= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 550DA60C67 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=okaya@codeaurora.org From: Sinan Kaya To: netdev@vger.kernel.org, timur@codeaurora.org, sulrich@codeaurora.org Subject: [PATCH v4 03/17] igbvf: eliminate duplicate barriers on weakly-ordered archs Date: Mon, 19 Mar 2018 22:42:18 -0400 Message-Id: <1521513753-7325-4-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521513753-7325-1-git-send-email-okaya@codeaurora.org> References: <1521513753-7325-1-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180319_194250_413657_CFAEB026 X-CRM114-Status: GOOD ( 12.16 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Sinan Kaya , intel-wired-lan@lists.osuosl.org, Jeff Kirsher , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Code includes wmb() followed by writel(). writel() already has a barrier on some architectures like arm64. This ends up CPU observing two barriers back to back before executing the register write. Since code already has an explicit barrier call, changing writel() to writel_relaxed(). Signed-off-by: Sinan Kaya Reviewed-by: Alexander Duyck --- drivers/net/ethernet/intel/igbvf/netdev.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/igbvf/netdev.c b/drivers/net/ethernet/intel/igbvf/netdev.c index 4214c15..edb1c34 100644 --- a/drivers/net/ethernet/intel/igbvf/netdev.c +++ b/drivers/net/ethernet/intel/igbvf/netdev.c @@ -251,7 +251,7 @@ static void igbvf_alloc_rx_buffers(struct igbvf_ring *rx_ring, * such as IA-64). */ wmb(); - writel(i, adapter->hw.hw_addr + rx_ring->tail); + writel_relaxed(i, adapter->hw.hw_addr + rx_ring->tail); } } @@ -2297,7 +2297,7 @@ static inline void igbvf_tx_queue_adv(struct igbvf_adapter *adapter, tx_ring->buffer_info[first].next_to_watch = tx_desc; tx_ring->next_to_use = i; - writel(i, adapter->hw.hw_addr + tx_ring->tail); + writel_relaxed(i, adapter->hw.hw_addr + tx_ring->tail); /* we need this if more than one processor can write to our tail * at a time, it synchronizes IO on IA64/Altix systems */