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 A4FCCC4332F for ; Wed, 23 Nov 2022 18:27:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239704AbiKWS04 (ORCPT ); Wed, 23 Nov 2022 13:26:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239650AbiKWS0o (ORCPT ); Wed, 23 Nov 2022 13:26:44 -0500 Received: from mail-pj1-x1034.google.com (mail-pj1-x1034.google.com [IPv6:2607:f8b0:4864:20::1034]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE0FE65875; Wed, 23 Nov 2022 10:26:39 -0800 (PST) Received: by mail-pj1-x1034.google.com with SMTP id q96-20020a17090a1b6900b00218b8f9035cso2573652pjq.5; Wed, 23 Nov 2022 10:26:39 -0800 (PST) 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=4as57wCvzop8813r3sliHAbaPmxH6ev1auHMwbNdJIo=; b=q5rmbKCsyxcX9QqNlu0c2EogSV6OPZ0rXgI0AWmUGlsn6T2cqXAl7igKciAlxyJ5ro GQh8tLG5VsdJgCYuyHiFuBPZbLx5qiYLxP11cqxAkaoivBXcaEMcD3Fl0SJwdjeJ0Kzm P2LbtGrMKAStFpoQhjZgkgoJ5P4A77HKfdBacxMCDQWLQZ4fOu9vujP2Tkw865riEvVy kHIaGkczm4l3CNWEB9lp2GUJgJvNiCmw/XEPl1vmtqklW3PHH6z8Xm1wiiUML/Jt8usc h+iAm8CYHS0m8fD9auKC9g62A6VYQL2l1AIM67SSjQ4nlVnwYPgVl3m8nqSRQCGCSgrR Ptdw== 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=4as57wCvzop8813r3sliHAbaPmxH6ev1auHMwbNdJIo=; b=Wl3slUTpfql25muK33pdj35BhtBAB/nA7SqQ+eNCvVUkj+6k5VJS6rrvVptZHxhR4X mLMDkHtePUmlkicLhbftHxdqwtyRAsYNtDm90X8J6x8ObPaYabHrnOD3iIoUYi2tRSHB KFfJR6UEtCAPZXvSi6vgoyRVZ2DD8usE2floVa5RoZDdHjvbIwOOWZ89EtBeSDOGjzse 1NLQ2cIdAk2zeLpO6vNvF4eynCy2OkF0Tbg2YX7FEcCYX55/NQINoQhePT85gA+ipXaQ 1X419QyHW8mS/sGwliCtn7u+GDGVRtpg4AKko8EOGknEJxE7aSsZYN9T6LOkx5RSJmr0 tZnA== X-Gm-Message-State: ANoB5pmUgdiMVu1voNDR5zO8dE7X6o9uVWEXHgzIayR7vxjAje9aCsQT cmfOITT6kkQ//Gz3NGPPNRM= X-Google-Smtp-Source: AA0mqf5xSyp/bZfSLwjBIn16APOxfb0kLIirC8uO3+PhiyCUyGEssHaxtO/NL6Yqh9yhIJw2uTXPnA== X-Received: by 2002:a17:903:25cb:b0:172:f722:8402 with SMTP id jc11-20020a17090325cb00b00172f7228402mr9899111plb.122.1669227998982; Wed, 23 Nov 2022 10:26:38 -0800 (PST) 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 k4-20020a170902694400b001891ea4d133sm7761660plt.12.2022.11.23.10.26.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Nov 2022 10:26:38 -0800 (PST) Sender: Tejun Heo Date: Wed, 23 Nov 2022 08:26:37 -1000 From: Tejun Heo To: Kemeng Shi Cc: josef@toxicpanda.com, axboe@kernel.dk, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 05/11] blk-throttle: simpfy low limit reached check in throtl_tg_can_upgrade Message-ID: References: <20221123060401.20392-1-shikemeng@huawei.com> <20221123060401.20392-6-shikemeng@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221123060401.20392-6-shikemeng@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 23, 2022 at 02:03:55PM +0800, Kemeng Shi wrote: > -static bool throtl_tg_can_upgrade(struct throtl_grp *tg) > +static bool throtl_tg_reach_low_limit(struct throtl_grp *tg, int rw) > { > struct throtl_service_queue *sq = &tg->service_queue; > - bool read_limit, write_limit; > + bool limit = tg->bps[rw][LIMIT_LOW] || tg->iops[rw][LIMIT_LOW]; > > /* > * if cgroup reaches low limit (if low limit is 0, the cgroup always > * reaches), it's ok to upgrade to next limit > */ > - read_limit = tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]; > - write_limit = tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]; > - if (!read_limit && !write_limit) > - return true; > - if (read_limit && sq->nr_queued[READ] && > - (!write_limit || sq->nr_queued[WRITE])) > - return true; > - if (write_limit && sq->nr_queued[WRITE] && > - (!read_limit || sq->nr_queued[READ])) > + return !limit || sq->nr_queued[rw]. > +} > + > +static bool throtl_tg_can_upgrade(struct throtl_grp *tg) > +{ > + if (throtl_tg_reach_low_limit(tg, READ) && > + throtl_tg_reach_low_limit(tg, WRITE)) Are the conditions being checked actually equivalent? If so, can you explicitly explain that these are equivalent conditions? If not, what are we changing exactly? Thanks. -- tejun