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=-4.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 BEE94C43381 for ; Mon, 25 Mar 2019 16:42:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F96C20863 for ; Mon, 25 Mar 2019 16:42:45 +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="Pl8B8yrz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729413AbfCYQmo (ORCPT ); Mon, 25 Mar 2019 12:42:44 -0400 Received: from mail-io1-f65.google.com ([209.85.166.65]:34690 "EHLO mail-io1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729123AbfCYQmo (ORCPT ); Mon, 25 Mar 2019 12:42:44 -0400 Received: by mail-io1-f65.google.com with SMTP id n11so8215136ioh.1 for ; Mon, 25 Mar 2019 09:42:44 -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=uoX8jNWSAXInEk3DZfyvqOe0hJmmnJ2TdvMsm5TZIwQ=; b=Pl8B8yrz0fH+bKiPi30eYEQMZ3KCQrd7fdd0aMkNKiqDi/feT58YGdBPZ4zayp/aX/ y078MTMROXpzz7O6oqrk7DzWA9JmNuA6kWM78xxvFfoFvl7ashlvG7UVbs8AAJ/AlGrV EEss0/Glw2zSsaLKqMyHolwEuSY9F9DX3KSUGppDwR+kKXW645GuPlPFa/zfYtWgC6kb MSdKlGdU+GPM5Pd2FaCnbh5YtyKU/5RcQRXKLuJCWAdMOc7NNEGqMB+lMNX++spNmUGm NJBN6Zlq855qAlLSTiKzGmSHYUovDiBFTceMr0/xJdi+IacmzllVpWTk9WKojqIbOpuH J7vQ== 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=uoX8jNWSAXInEk3DZfyvqOe0hJmmnJ2TdvMsm5TZIwQ=; b=C3fNhEXllNK5RT4PJ747W3aY9475+rLEbnPms+Y4DuGUpROQlLtd7CjMkht4g9zKlX xh1hsWcQbejkWDVA5O2lJXLLIh8BrLsD+zS3zsQgNfTFavSw6ccOfcpXQfSgTz/42W+F 8lXJsCR3jW8MI3mmx4j5zHa0JbO5orhX1XEQL+714XC3pBKq14+NLJlglVx8WbPtI3V3 szHlQ/lGy1DMACv/BQOBEC4wg9fUUtpErYFbyTAmqQdwFPuiTV+2bIfBV2Ff6S9LSGl2 w6PV5pZ/o6SSv0H6bhASlyS9vlKCZN6yJNjnp72pILpdO4E3MoxtHk8HKZ9lwpvqxBpZ NLug== X-Gm-Message-State: APjAAAU0PQ3dP3EIzJXesfZwfR0bf7Z8OiFnGWLEy/5Y47rpb0zpKuEn LIC7fqG1Ko+Gn02454sqURHwv5QzuDxw+g== X-Google-Smtp-Source: APXvYqwiw2JmOUOh+PoS+kDOuSHDMKIWQM/cNsk6vZow1vcjYi3vwUifxb4SdmAf+uDSnHcV2h1ULQ== X-Received: by 2002:a6b:660e:: with SMTP id a14mr16743517ioc.136.1553532162969; Mon, 25 Mar 2019 09:42:42 -0700 (PDT) Received: from [192.168.1.158] ([216.160.245.98]) by smtp.gmail.com with ESMTPSA id k18sm5117452itk.38.2019.03.25.09.42.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Mar 2019 09:42:42 -0700 (PDT) Subject: Re: [PATCH] blk-mq: fix sbitmap ws_active for shared tags To: Bart Van Assche , "linux-block@vger.kernel.org" Cc: Omar Sandoval References: <1553531987.118779.9.camel@acm.org> From: Jens Axboe Message-ID: <0ef38015-d57c-fdbd-6c1e-6cf2ceec3ec4@kernel.dk> Date: Mon, 25 Mar 2019 10:42:41 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <1553531987.118779.9.camel@acm.org> Content-Type: text/plain; charset=UTF-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 3/25/19 10:39 AM, Bart Van Assche wrote: > On Mon, 2019-03-25 at 10:22 -0600, Jens Axboe wrote: >> We now wrap sbitmap waitqueues in an active counter, so we can avoid >> iterating wakeups unless we have waiters there. This works as long as >> everyone that's manipulating the waitqueues use the proper helpers. For >> the tag wait case for shared tags, however, we add ourselves to the >> waitqueue without incrementing/decrementing the ->ws_active count. This >> means that wakeups can take a long time to happen. >> >> Fix this by manually doing the inc/dec as needed for the wait queue >> handling. >> >> Fixes: 5d2ee7122c73 ("sbitmap: optimize wakeup check") >> Signed-off-by: Jens Axboe > > Hi Jens, > > Since commit 5d2ee7122c73 went upstream in kernel v5.0, does this patch need > a "Cc: stable" tag? I guess it does, I'll add it. -- Jens Axboe