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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 30603C433FE for ; Tue, 11 Oct 2022 17:02:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229605AbiJKRCg (ORCPT ); Tue, 11 Oct 2022 13:02:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33590 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229923AbiJKRCd (ORCPT ); Tue, 11 Oct 2022 13:02:33 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2740E43AC7; Tue, 11 Oct 2022 10:02:32 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id t10-20020a17090a4e4a00b0020af4bcae10so13771897pjl.3; Tue, 11 Oct 2022 10:02:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date:message-id :reply-to; bh=8eRz9lupDvDdx3arCB9zqmOVqRgcbX6KAfstA0H6aeE=; b=H93cQgxKhWvRmxhNCyPVUJ0JihVjsjM9VYphS6RAehXSGKKG3m/DC7W9mffVNn/pqQ aTq45+gyvzY0A8AvN/kZw4ZKR4qG+GrBPDpyfVLCvHYGHxu8MHYaSruImPjns902FG0y +kHDLZSD5VcrQYK1p+DjyIm3EOSg3HsypzNIIWFnfd6UUFLTmVhZ0iGBprYTWY8yG4Jw RGzVkmwqq2+DjEYeLn7EfNg1daDE9kqN4y2bG3wejSwVvENGXPHLE8Mr2jkdNJV72UG8 qZeB1bF+GlfqgHYc2ACJSOVebUG/MPStUnXmbsMR0AOAV4ish0uqH8Vwdo+dL563BzhJ 5J6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=8eRz9lupDvDdx3arCB9zqmOVqRgcbX6KAfstA0H6aeE=; b=5BCKsi4jzMnVRW/7JwSDuqdNiNnGpj7mrPGO77TkMgSMRbVjhRqKUW0jb2t8lYKHoE Mr6T0t3s7tMiRC5YYeFCfjFQuf9zEzeaKjGHGaqvN1GLtrjOazGPafa4CtqRgjqA5xro aWMMR41OiAnwNkraVOimnq54m7ROcze9CCnLuBmYkgSF2BjR89GQahlpziVR0bs153Ge dByUNWkKMLfhNt/PnG7BdTGZpTjTjm6Nn//4YCDTkr699qBKND8+M7sB7QynilJP21aR kqatviUDCqT1LRC10TMEnDdroiTkshXacCfssZ51wk8u5ff/u7/VVXoK7Kw85r8Wg7C3 Uibw== X-Gm-Message-State: ACrzQf0I9lNf6lE+S5Q06bypp8k98xDr3+b/iY3xFHTZgqQGyfmS0jOF yCuycXd6XFSsS92r8K6bFm4= X-Google-Smtp-Source: AMsMyM7s7/eOhf2xT24hBT6++YnR4amW46bPXSBch6LK2z+6SxfxKBgWKDjgQH0Gq21wTGo+Kk+Stg== X-Received: by 2002:a17:902:6b81:b0:182:df88:e6ce with SMTP id p1-20020a1709026b8100b00182df88e6cemr9030343plk.173.1665507752185; Tue, 11 Oct 2022 10:02:32 -0700 (PDT) Received: from localhost (2603-800c-1a02-1bae-a7fa-157f-969a-4cde.res6.spectrum.com. [2603:800c:1a02:1bae:a7fa:157f:969a:4cde]) by smtp.gmail.com with ESMTPSA id y8-20020a17090322c800b00176b63535adsm8951512plg.260.2022.10.11.10.02.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Oct 2022 10:02:31 -0700 (PDT) Sender: Tejun Heo Date: Tue, 11 Oct 2022 07:02:30 -1000 From: Tejun Heo To: Yu Kuai Cc: axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai3@huawei.com, yi.zhang@huawei.com Subject: Re: [PATCH -next 4/5] blk-iocost: bypass if only one cgroup issues io Message-ID: References: <20221011083547.1831389-1-yukuai1@huaweicloud.com> <20221011083547.1831389-5-yukuai1@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221011083547.1831389-5-yukuai1@huaweicloud.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Oct 11, 2022 at 04:35:46PM +0800, Yu Kuai wrote: > From: Yu Kuai > > In this special case, there is no need to throttle io. > > Signed-off-by: Yu Kuai > --- > block/blk-iocost.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/block/blk-iocost.c b/block/blk-iocost.c > index 5acc5f13bbd6..32e7e416d67c 100644 > --- a/block/blk-iocost.c > +++ b/block/blk-iocost.c > @@ -2564,8 +2564,13 @@ static void ioc_rqos_throttle(struct rq_qos *rqos, struct bio *bio) > bool use_debt, ioc_locked; > unsigned long flags; > > - /* bypass IOs if disabled, still initializing, or for root cgroup */ > - if (!ioc->enabled || !iocg || !iocg->level) > + /* > + * bypass IOs if disabled, still initializing, for root cgroup, > + * or the cgroup is the only cgroup with io. > + */ > + if (!ioc->enabled || !iocg || !iocg->level || > + (iocg->hweight_inuse == WEIGHT_ONE && > + atomic_read(&ioc->hweight_gen) == iocg->hweight_gen)) I'm not sure about this one. Bypassing here means that we lose track of how much IO it's issuing which can affect future throttling decisions, right? Thanks. -- tejun