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(p200300ea8f0655007ca20fb69bdef4e5.dip0.t-ipconnect.de. [2003:ea:8f06:5500:7ca2:fb6:9bde:f4e5]) by smtp.googlemail.com with ESMTPSA id j10sm869109wmj.7.2021.01.11.13.35.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Jan 2021 13:35:58 -0800 (PST) To: Paul Thomas , Nicolas Ferre , Claudiu Beznea , "David S. Miller" , Jakub Kicinski , Russell King , Palmer Dabbelt , Paul Walmsley , netdev@vger.kernel.org, linux-kernel , linux-riscv@lists.infradead.org References: From: Heiner Kallweit Subject: Re: net: macb: can macb use __napi_schedule_irqoff() instead of __napi_schedule() Message-ID: Date: Mon, 11 Jan 2021 22:35:54 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210111_163603_701603_4BCAE517 X-CRM114-Status: GOOD ( 15.16 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On 11.01.2021 20:45, Paul Thomas wrote: > Hello, recently I was doing a lot of tracing/profiling to understand > an issue we were having. Anyway, during this I ran across > __napi_schedule_irqoff() where the comment in dev.c says "Variant of > __napi_schedule() assuming hard irqs are masked". > > It looks like the queue_writel(queue, IDR, bp->rx_intr_mask); call > just before the __napi_schedule() call in macb_main.c is doing this > hard irq masking? So could it change to be like this? > It's unsafe under forced irq threading. There has been a number of discussions about this topic in the past. > --- a/drivers/net/ethernet/cadence/macb_main.c > +++ b/drivers/net/ethernet/cadence/macb_main.c > @@ -1616,7 +1623,7 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id) > > if (napi_schedule_prep(&queue->napi)) { > netdev_vdbg(bp->dev, "scheduling RX softirq\n"); > - __napi_schedule(&queue->napi); > + __napi_schedule_irqoff(&queue->napi); > } > } > > -Paul > _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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=-9.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 57731C433E9 for ; Mon, 11 Jan 2021 21:36:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 227EC225AC for ; Mon, 11 Jan 2021 21:36:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731043AbhAKVgm (ORCPT ); Mon, 11 Jan 2021 16:36:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726473AbhAKVgl (ORCPT ); Mon, 11 Jan 2021 16:36:41 -0500 Received: from mail-wr1-x42f.google.com (mail-wr1-x42f.google.com [IPv6:2a00:1450:4864:20::42f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77DAEC061786; Mon, 11 Jan 2021 13:36:00 -0800 (PST) Received: by mail-wr1-x42f.google.com with SMTP id d26so247891wrb.12; Mon, 11 Jan 2021 13:36:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=to:references:from:subject:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=JjhX+TMUEJN1XvProD26j5/JejgcKCm/i/sK2lOcnvk=; b=gbuZuqib606BmRbnJWObIfxMPb/hm83LrUIPbHo2kk8Ct3ps306mxAM/5Go2sfuESr Z9gUv5yHCIJadsOex7tmNTCuJVglZEVSoRr4PIZUrSEASmwvlVQjvAOuxIP5VQM55oTr /OZC6dVhSOavZMlYuNwf8q4ALHIP+aDH66onsZl6n31SmmtAKi0gVzA1lzhfbal+RGCN NbM2ni/kPftZNkITZSwk0ZBktb/6XWkkwiV0szX7qb3QKpIZfdnHcw8zoN738Mf5K/mt A5i8OTvx8O4EW4g7vraLkSM0PVCPuvxjyHqZKHE9PLJRTA/m8KCTio54HuPj1/uIqYs9 rNXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:references:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=JjhX+TMUEJN1XvProD26j5/JejgcKCm/i/sK2lOcnvk=; b=JsowEhnD/GoFL1/Wla5zag7nX1IJC5BzU5ZuE8hkjizgTZYAIZltXTOG17px3Ds3RE FiZqswtPafzdbZ37fhbkLhPWoRLd9OvgOnl6iQkx/nikT1XsNywQoW/UMyS6eXAMTkXn kr2FtFa4sli73iwDYlKneLiljPT6mpL+vVIiYMFHYrXe5nx1GGpxrqIknsa190a4+zU7 QBJwZItN9OkdQyhHVZg44aelPvtLl4Yv2FfTetqxeHzThYoFK8gO6w9uUHwVZ7FRMBuU KHjsfB1ZYsDzQszN6A3y1o7wPLgh5A9Wwtma/5c6YQoI+tOqIeOMhl0hNlYZz3euYDeG 2OKg== X-Gm-Message-State: AOAM53182v4YiltU+obCFcBbW99tg7JQ5f03bYnLYaVtgjjtTDaHloVh Wi1+269th6xglBqvA0c5pNU= X-Google-Smtp-Source: ABdhPJxKVSv0DdrJagzcdGXIj4f8cDmyg+28M0v95gXqEiBzxqfepXB4KE7PWXXraVlAuEnOfArupA== X-Received: by 2002:a5d:6cad:: with SMTP id a13mr955104wra.275.1610400959259; Mon, 11 Jan 2021 13:35:59 -0800 (PST) Received: from ?IPv6:2003:ea:8f06:5500:7ca2:fb6:9bde:f4e5? (p200300ea8f0655007ca20fb69bdef4e5.dip0.t-ipconnect.de. [2003:ea:8f06:5500:7ca2:fb6:9bde:f4e5]) by smtp.googlemail.com with ESMTPSA id j10sm869109wmj.7.2021.01.11.13.35.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Jan 2021 13:35:58 -0800 (PST) To: Paul Thomas , Nicolas Ferre , Claudiu Beznea , "David S. Miller" , Jakub Kicinski , Russell King , Palmer Dabbelt , Paul Walmsley , netdev@vger.kernel.org, linux-kernel , linux-riscv@lists.infradead.org References: From: Heiner Kallweit Subject: Re: net: macb: can macb use __napi_schedule_irqoff() instead of __napi_schedule() Message-ID: Date: Mon, 11 Jan 2021 22:35:54 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11.01.2021 20:45, Paul Thomas wrote: > Hello, recently I was doing a lot of tracing/profiling to understand > an issue we were having. Anyway, during this I ran across > __napi_schedule_irqoff() where the comment in dev.c says "Variant of > __napi_schedule() assuming hard irqs are masked". > > It looks like the queue_writel(queue, IDR, bp->rx_intr_mask); call > just before the __napi_schedule() call in macb_main.c is doing this > hard irq masking? So could it change to be like this? > It's unsafe under forced irq threading. There has been a number of discussions about this topic in the past. > --- a/drivers/net/ethernet/cadence/macb_main.c > +++ b/drivers/net/ethernet/cadence/macb_main.c > @@ -1616,7 +1623,7 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id) > > if (napi_schedule_prep(&queue->napi)) { > netdev_vdbg(bp->dev, "scheduling RX softirq\n"); > - __napi_schedule(&queue->napi); > + __napi_schedule_irqoff(&queue->napi); > } > } > > -Paul >