From patchwork Thu Dec 6 18:18:17 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Valente X-Patchwork-Id: 10716553 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3A56F15A6 for ; Thu, 6 Dec 2018 18:18:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2CBB12F0B5 for ; Thu, 6 Dec 2018 18:18:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1E4A92F0CD; Thu, 6 Dec 2018 18:18:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A92C42F0B5 for ; Thu, 6 Dec 2018 18:18:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725928AbeLFSSd (ORCPT ); Thu, 6 Dec 2018 13:18:33 -0500 Received: from mail-wm1-f68.google.com ([209.85.128.68]:35740 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725908AbeLFSSc (ORCPT ); Thu, 6 Dec 2018 13:18:32 -0500 Received: by mail-wm1-f68.google.com with SMTP id c126so2060840wmh.0 for ; Thu, 06 Dec 2018 10:18:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=x43sXtJKZfNFoIjdrUgoUaVnk5ggsAeA66Y8BOJoHGs=; b=L05+vlXczJ/Fn+1uVTe360qP/sxvCJn17zo6TmqqYeH1VpEdeYM0vihF8pxC1T9TLz YEhfIXkHvoK4SdBBL30hiTxA1pTTG7isKBu64WV+w9bRAhnMNhvzovjcf780CPnEJH7e wnAFXCRsfCX9w/wwzv+oGqDfnFs3Pe5+cLz+M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=x43sXtJKZfNFoIjdrUgoUaVnk5ggsAeA66Y8BOJoHGs=; b=aTGorSdJBmbris0GKrZqFxSoPxMsA7s89z61nsnJU6rEcmXJ/GDyhJ8jl6DQRiNQsS XLRHH33/z11/aCumPNVqlxo9EkO8PfQo69CVj4J9k2vxMbHwxJPNlVU6HpPWpMkSs2So izovhl0425IBguKZU8w9D649mJes0PxOmg34QAtoWTYYK56BQwg5K5fPzKyVhwGlXnxK ayjwBNGePjM5Io8QLCb3G3RxOVzjpwS4ijx6Bg95QzwV+I3g9pcjauryjgK+HF8VI9px zcjz2aVQDO4es0GzuT2iAXxlvlroxh5+g3D714v6QLyFfexSr5QH9D0xk35DYtCxqkFc IAUQ== X-Gm-Message-State: AA+aEWZK88eJB2ZaGuljqiY8wTyHvhMjvfGwSBoJhp/M2wyerR5X57Fm POmuZxMgLRXKMEThOKvzd1k1sA== X-Google-Smtp-Source: AFSGD/WCif5TaD8RKNkznpmLlzDPi+AXGqmz6CoiMyVGWdbAYWJKGANRR8xj5agFllsam95mxsIqtg== X-Received: by 2002:a7b:c315:: with SMTP id k21mr19919765wmj.145.1544120311088; Thu, 06 Dec 2018 10:18:31 -0800 (PST) Received: from localhost.localdomain (146-241-0-214.dyn.eolo.it. [146.241.0.214]) by smtp.gmail.com with ESMTPSA id w18sm727733wru.54.2018.12.06.10.18.29 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 06 Dec 2018 10:18:30 -0800 (PST) From: Paolo Valente To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, broonie@kernel.org, bfq-iosched@googlegroups.com, oleksandr@natalenko.name, federico@willer.it, Paolo Valente Subject: [PATCH BUGFIX 0/2] bfq: fix unbalanced decrements causing loss of throughput Date: Thu, 6 Dec 2018 19:18:17 +0100 Message-Id: <20181206181819.11148-1-paolo.valente@linaro.org> X-Mailer: git-send-email 2.16.1 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hi Jens, the first patch in this series fixes an error in the decrementing of the counter of the number of groups with pending I/O. This wrong decrement caused loss of throughput or, less likely, of control on I/O. The second patch is a fix of some wrong comments, which somehow contributed to making the above bug more difficult to find. Thanks, Paolo Paolo Valente (2): block, bfq: fix decrement of num_active_groups block, bfq: fix comments on __bfq_deactivate_entity block/bfq-iosched.c | 76 +++++++++++++++++++++++++++++++++++++---------------- block/bfq-iosched.h | 51 +++++++++++++++++++++++++++++++++-- block/bfq-wf2q.c | 16 ++++++----- 3 files changed, 112 insertions(+), 31 deletions(-) --- 2.16.1