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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 870DEC282C4 for ; Wed, 13 Feb 2019 02:38:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 53EFC222C7 for ; Wed, 13 Feb 2019 02:38:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025512; bh=7OZR+Bc0SwMAlhu4115yXj/DAPT0IKMwW/5ObjDAvp4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=HTP6qZ85dasqfsElrIvNG47qVaZ9VPxKCAWLvslP/olDBh4ctJ7tU6EM6Ro6N6gbg t8RT3IQfPx9sKxx/va/62iLRC4nP7k3GhyOO6X/0NjUJwq9UnWaTV369JZtUMXUYPB moy113aH+PcT/JOvJWB/KFLIe5xtR463OKzC3tvs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388546AbfBMCia (ORCPT ); Tue, 12 Feb 2019 21:38:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:41956 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388511AbfBMCiZ (ORCPT ); Tue, 12 Feb 2019 21:38:25 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4857B206B6; Wed, 13 Feb 2019 02:38:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550025504; bh=7OZR+Bc0SwMAlhu4115yXj/DAPT0IKMwW/5ObjDAvp4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NM/Q9BQSKUTTEL4OLPYc3svgCd6ZTdjaR/uZDqd/Ctu4en0hdg6bERMXHx3IkLBMe LCw4lZ5fsQGQmzWGdxZF85SelsYarDjRMO8Uy5Cy/ZM4bmw7+lvrqt0heEsx1xee2C 5gRpRhf/1KH3BVSlddik8b/OGwoL9i8gQXY2Jwbs= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jose Abreu , Joao Pinto , "David S . Miller" , Giuseppe Cavallaro , Alexandre Torgue , Jose Abreu , Sasha Levin , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 49/83] net: stmmac: Prevent RX starvation in stmmac_napi_poll() Date: Tue, 12 Feb 2019 21:36:27 -0500 Message-Id: <20190213023701.20286-49-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190213023701.20286-1-sashal@kernel.org> References: <20190213023701.20286-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jose Abreu [ Upstream commit fa0be0a43f101888ac677dba31b590963eafeaa1 ] Currently, TX is given a budget which is consumed by stmmac_tx_clean() and stmmac_rx() is given the remaining non-consumed budget. This is wrong and in case we are sending a large number of packets this can starve RX because remaining budget will be low. Let's give always the same budget for RX and TX clean. While at it, check if we missed any interrupts while we were in NAPI callback by looking at DMA interrupt status. Cc: Joao Pinto Cc: David S. Miller Cc: Giuseppe Cavallaro Cc: Alexandre Torgue Signed-off-by: Jose Abreu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- .../net/ethernet/stmicro/stmmac/stmmac_main.c | 27 ++++++++++--------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 24ae244c2ee3..123b74e25ed8 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -3522,27 +3522,28 @@ static int stmmac_napi_poll(struct napi_struct *napi, int budget) struct stmmac_channel *ch = container_of(napi, struct stmmac_channel, napi); struct stmmac_priv *priv = ch->priv_data; - int work_done = 0, work_rem = budget; + int work_done, rx_done = 0, tx_done = 0; u32 chan = ch->index; priv->xstats.napi_poll++; - if (ch->has_tx) { - int done = stmmac_tx_clean(priv, work_rem, chan); + if (ch->has_tx) + tx_done = stmmac_tx_clean(priv, budget, chan); + if (ch->has_rx) + rx_done = stmmac_rx(priv, budget, chan); - work_done += done; - work_rem -= done; - } - - if (ch->has_rx) { - int done = stmmac_rx(priv, work_rem, chan); + work_done = max(rx_done, tx_done); + work_done = min(work_done, budget); - work_done += done; - work_rem -= done; - } + if (work_done < budget && napi_complete_done(napi, work_done)) { + int stat; - if (work_done < budget && napi_complete_done(napi, work_done)) stmmac_enable_dma_irq(priv, priv->ioaddr, chan); + stat = stmmac_dma_interrupt_status(priv, priv->ioaddr, + &priv->xstats, chan); + if (stat && napi_reschedule(napi)) + stmmac_disable_dma_irq(priv, priv->ioaddr, chan); + } return work_done; } -- 2.19.1