From patchwork Fri May 8 12:31:10 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 226287 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, 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 35F4EC38A2A for ; Fri, 8 May 2020 12:39:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1189524968 for ; Fri, 8 May 2020 12:39:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588941563; bh=L6nWKzvXisLJ9SUYs6xKsGRTVvesEBjOfyTT5CiIIL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Cu/FZHpVqWm0b7Djt/gfu2wNFJxWTz6gW0kNWrpkO/yRNJssup6F7lKYFucCfKs7E PPQ17OKUwSdEfOrm4KmL50JbukJZuQF5z6WRFPGcoBg7rEYzyO2MJP0taX6jYVtunA AOBudOJyu4hrQNQ2O/9u/dXBVfLgDQZRY9Jeh0bw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728555AbgEHMjT (ORCPT ); Fri, 8 May 2020 08:39:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:58066 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727889AbgEHMjS (ORCPT ); Fri, 8 May 2020 08:39:18 -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 B09C021835; Fri, 8 May 2020 12:39:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588941556; bh=L6nWKzvXisLJ9SUYs6xKsGRTVvesEBjOfyTT5CiIIL0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l/bxdruIUT1WB7xnUaNWoOvnBuR3YtjswUk0aEPQpeSI437ddjwJjvPUkxH+fFBBS iZyl5R7EVyUmznDx7I/TFQHma6tfBtL3hdeFV8gE279Yyj/WCAapB5NzgVC17OPJL+ 7XTBSzX180iS8QbuaW78sBSiqUDlqyR62069LqFQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eli Cohen , Saeed Mahameed , "David S. Miller" Subject: [PATCH 4.4 079/312] net/mlx5e: Fix blue flame quota logic Date: Fri, 8 May 2020 14:31:10 +0200 Message-Id: <20200508123130.075466608@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200508123124.574959822@linuxfoundation.org> References: <20200508123124.574959822@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eli Cohen commit 0ca00fc1f808602137dc6d51f17747b3bb0fc34d upstream. Blue flame is a latency enhancement feature that allows the driver to write the packet data directly to the NIC's registers thus making the read of the packet data from host memory redundant. We maintain a quota for the blue flame which is reloaded whenever we identify that the hardware is processing send requests and processes them fast enough so by the time we post the next send request it was able to process all the pending ones. This indicates that the hardware is capable of processing more blue flame requests efficiently. The blue flame quota is decremented whenever we send using blue flame. The current code erroneously clears the budget if we did not use blue flame for the current post send operation and we fix it here. Fixes: 88a85f99e51f ('net/mlx5e: TX latency optimization to save DMA reads') Signed-off-by: Eli Cohen Signed-off-by: Saeed Mahameed Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c @@ -290,7 +290,8 @@ static netdev_tx_t mlx5e_sq_xmit(struct while ((sq->pc & wq->sz_m1) > sq->edge) mlx5e_send_nop(sq, false); - sq->bf_budget = bf ? sq->bf_budget - 1 : 0; + if (bf) + sq->bf_budget--; sq->stats.packets++; return NETDEV_TX_OK;