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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 EE964C48BD6 for ; Wed, 26 Jun 2019 22:26:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C434D21743 for ; Wed, 26 Jun 2019 22:26:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="Wl4IVoax" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726587AbfFZWZ7 (ORCPT ); Wed, 26 Jun 2019 18:25:59 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:39223 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726481AbfFZWZ7 (ORCPT ); Wed, 26 Jun 2019 18:25:59 -0400 Received: by mail-pl1-f196.google.com with SMTP id b7so107903pls.6 for ; Wed, 26 Jun 2019 15:25:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=yXH77KA1A1IW9jOBzRWJZbCLzrA9uThM81uS89UYoSU=; b=Wl4IVoaxRwbRhirOgliE8eXCyv1QrjjOgbhe7ORjLu4fDmYPjY8/Nw2F3YNETiuhFW NLpzmM+qzD3PNW95ODlLblQp+YcLk4s2ZwwOTg1bhTHTUubVpSQm6FIqWAMDe/9DVGKg rn2eK8pZGhtEVuitZj8wPXm9FP0/6qKIGWCX+A07/FU+Pq7kQRe/NqeN3Kz42cyEVO3A uKZ8SPSD+vksqg+YDUoAAywVZD8g0YElGrWu2RTbLRKKT7s8IK2OTJOGsR7wW5J0EBJr vkPHnk79i9efYSuuJJfFDlJU9eFZb90NXLIF7AO0tq+M3ws5Hv5YjFWPvTpFmFaFNqkj Amuw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=yXH77KA1A1IW9jOBzRWJZbCLzrA9uThM81uS89UYoSU=; b=Hj4XRsXwvcc4JaZ6gmGdsQi63OsynkoLaheilnF1GiCI/QKUYdB5oo4UOnHRxFpOXe E0VLiHItqeX/v058Px6sOI7MskITWmtdDk5VJix5cBvn1haPqhcjMcpTrs0la2l9n2ys BuC4n+4E/MpbrPMQTqZeiEUvVOhPs940kTAS8cw8NKdtwhk1QNj/viWdC3fKcdJV5Egh r1WhNyRKGsXV6fMAT9LeiKL677rgG0DQ508IrFgidnZVRTQ1UA33/IuKUs9OVa0BLN7z h0NBQrJNbo7/ZpmpXplXqdH6Zc3l3qnJ98KRN5z6MhsqVZsQqxkZj0GXjvJpKPIF2djS ccNw== X-Gm-Message-State: APjAAAUauSILnXrghayyUZ2ox9st2v35yogFuijMJuge9ha4BYLDLqJm qTYaFenKd5IBnSwD2FzRQijx+fl9pJibdg== X-Google-Smtp-Source: APXvYqyFASo6/HuehlUHfhZusl2VH67NgnB7FpHMLSsvKvEp8xsjLhjEQg5Hu6ZMjSm/ZN4I7gMA/g== X-Received: by 2002:a17:902:d20f:: with SMTP id t15mr472750ply.11.1561587958017; Wed, 26 Jun 2019 15:25:58 -0700 (PDT) Received: from [192.168.1.121] (66.29.164.166.static.utbb.net. [66.29.164.166]) by smtp.gmail.com with ESMTPSA id t2sm124731pgo.61.2019.06.26.15.25.55 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Jun 2019 15:25:56 -0700 (PDT) Subject: Re: [PATCH] block, bfq: Init saved_wr_start_at_switch_to_srt in unlikely case To: Douglas Anderson , Paolo Valente Cc: groeck@chromium.org, drinkcat@chromium.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190626195919.107425-1-dianders@chromium.org> From: Jens Axboe Message-ID: <8a108498-77ec-1164-b5ed-80d791f60119@kernel.dk> Date: Wed, 26 Jun 2019 16:25:55 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.1 MIME-Version: 1.0 In-Reply-To: <20190626195919.107425-1-dianders@chromium.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/26/19 1:59 PM, Douglas Anderson wrote: > Some debug code suggested by Paolo was tripping when I did reboot > stress tests. Specifically in bfq_bfqq_resume_state() > "bic->saved_wr_start_at_switch_to_srt" was later than the current > value of "jiffies". A bit of debugging showed that > "bic->saved_wr_start_at_switch_to_srt" was actually 0 and a bit more > debugging showed that was because we had run through the "unlikely" > case in the bfq_bfqq_save_state() function. > > Let's init "saved_wr_start_at_switch_to_srt" in the unlikely case to > something sane. > > NOTE: this fixes no known real-world errors. Applied, thanks. -- Jens Axboe