From patchwork Wed Mar 21 18:56:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sinan Kaya X-Patchwork-Id: 889010 X-Patchwork-Delegate: jeffrey.t.kirsher@intel.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=osuosl.org (client-ip=140.211.166.133; helo=hemlock.osuosl.org; envelope-from=intel-wired-lan-bounces@osuosl.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=codeaurora.org header.i=@codeaurora.org header.b="FOSpMyrq"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="FOSpMyrq"; dkim-atps=neutral Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 405zY913XKz9s0t for ; Thu, 22 Mar 2018 05:56:29 +1100 (AEDT) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 5536D89F59; Wed, 21 Mar 2018 18:56:27 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id gWc1LpWJZ4R7; Wed, 21 Mar 2018 18:56:25 +0000 (UTC) Received: from ash.osuosl.org (ash.osuosl.org [140.211.166.34]) by hemlock.osuosl.org (Postfix) with ESMTP id 9F43889F37; Wed, 21 Mar 2018 18:56:25 +0000 (UTC) X-Original-To: intel-wired-lan@lists.osuosl.org Delivered-To: intel-wired-lan@lists.osuosl.org Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by ash.osuosl.org (Postfix) with ESMTP id 4647B1C005F for ; Wed, 21 Mar 2018 18:56:24 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 4322887CE2 for ; Wed, 21 Mar 2018 18:56:24 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UQrp0r0q0wdh for ; Wed, 21 Mar 2018 18:56:22 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from smtp.codeaurora.org (smtp.codeaurora.org [198.145.29.96]) by fraxinus.osuosl.org (Postfix) with ESMTPS id E0B3687C9A for ; Wed, 21 Mar 2018 18:56:22 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1000) id B596D607A2; Wed, 21 Mar 2018 18:56:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521658582; bh=2H9QFEk86A9ARflRws4pF/kG3G744iXzzqx4++hiQfI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FOSpMyrq2fQreCRT3PgrYJD7GoHXuxdkvoEovT/i9DgzBl3cJdY52WzimStAJNk5L 0OFo1hWhs2qW7vEhlKVnnc8n1QdiqQmGb9nHxBS//AYNAfLbJXhx17eIhwF2/llhp0 1MokASVdJDSDxMYCzgH4Ryq3Ekc50rjS+TdmKryc= 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 5484060F61; Wed, 21 Mar 2018 18:56:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1521658582; bh=2H9QFEk86A9ARflRws4pF/kG3G744iXzzqx4++hiQfI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FOSpMyrq2fQreCRT3PgrYJD7GoHXuxdkvoEovT/i9DgzBl3cJdY52WzimStAJNk5L 0OFo1hWhs2qW7vEhlKVnnc8n1QdiqQmGb9nHxBS//AYNAfLbJXhx17eIhwF2/llhp0 1MokASVdJDSDxMYCzgH4Ryq3Ekc50rjS+TdmKryc= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 5484060F61 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: jeffrey.t.kirsher@intel.com Date: Wed, 21 Mar 2018 14:56:06 -0400 Message-Id: <1521658572-26354-3-git-send-email-okaya@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1521658572-26354-1-git-send-email-okaya@codeaurora.org> References: <1521658572-26354-1-git-send-email-okaya@codeaurora.org> MIME-Version: 1.0 Subject: [Intel-wired-lan] [PATCH REPOST v4 2/7] ixgbe: eliminate duplicate barriers on weakly-ordered archs X-BeenThere: intel-wired-lan@osuosl.org X-Mailman-Version: 2.1.24 Precedence: list List-Id: Intel Wired Ethernet Linux Kernel Driver Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: sulrich@codeaurora.org, netdev@vger.kernel.org, timur@codeaurora.org, linux-kernel@vger.kernel.org, Sinan Kaya , intel-wired-lan@lists.osuosl.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org Errors-To: intel-wired-lan-bounces@osuosl.org Sender: "Intel-wired-lan" Code includes wmb() followed by writel() in multiple places. 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 Tested-by: Andrew Bowers --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index 0da5aa2..58ed70f 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -1692,7 +1692,7 @@ void ixgbe_alloc_rx_buffers(struct ixgbe_ring *rx_ring, u16 cleaned_count) * such as IA-64). */ wmb(); - writel(i, rx_ring->tail); + writel_relaxed(i, rx_ring->tail); } } @@ -2453,7 +2453,7 @@ static int ixgbe_clean_rx_irq(struct ixgbe_q_vector *q_vector, * know there are new descriptors to fetch. */ wmb(); - writel(ring->next_to_use, ring->tail); + writel_relaxed(ring->next_to_use, ring->tail); xdp_do_flush_map(); } @@ -8078,7 +8078,7 @@ static int ixgbe_tx_map(struct ixgbe_ring *tx_ring, ixgbe_maybe_stop_tx(tx_ring, DESC_NEEDED); if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) { - writel(i, tx_ring->tail); + writel_relaxed(i, 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 @@ -10014,7 +10014,7 @@ static void ixgbe_xdp_flush(struct net_device *dev) * are new descriptors to fetch. */ wmb(); - writel(ring->next_to_use, ring->tail); + writel_relaxed(ring->next_to_use, ring->tail); return; }