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[23.128.96.18]) by mx.google.com with ESMTP id hq27si577001ejc.5.2020.12.02.11.14.15; Wed, 02 Dec 2020 11:14:39 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=cuyop+6G; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388080AbgLBTLv (ORCPT + 99 others); Wed, 2 Dec 2020 14:11:51 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387739AbgLBTLu (ORCPT ); Wed, 2 Dec 2020 14:11:50 -0500 Received: from mail-qk1-x744.google.com (mail-qk1-x744.google.com [IPv6:2607:f8b0:4864:20::744]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A50EDC0613CF; Wed, 2 Dec 2020 11:11:10 -0800 (PST) Received: by mail-qk1-x744.google.com with SMTP id z188so2318816qke.9; Wed, 02 Dec 2020 11:11:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=v5D6PtLHVVQdV/ubjkOzdJ2GbL8TD6flP6rlB6RAW04=; b=cuyop+6GEYsJfkfCvrlT56PR6leruYXY5xPg4Fdmi14/OZPEhEcIUgeCsS0pTNj7Eh jzkIP1A/NrdAr19D53DRdBUsnOAOhlNewUybMARKFcP77devwmFS1CqYYaN7HC4m0lgi DFbVKFSeopvdwV5JccZt++HutFbOhhiVtFp3yMOsECMbScMuv1/v1XE6VDoPwzjAowuL 75XHn4iGJsiobXi24yrPTzCNOk/Mzrp+2cWJ1wW0OBGhuX7sTcpU6W/a++z4rZypJnV5 xWMyeP1DfqXvkJB4MZcZsY3WyzipNR0PEe7As0InJw/dJbEJ4S8+5F1Az9sEW9b7Vrnl Cwcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=v5D6PtLHVVQdV/ubjkOzdJ2GbL8TD6flP6rlB6RAW04=; b=SWKH8gIAhDKovQ1+rWQaagnHk19acKM0NS1KfMjdhsqWczFJuv7bFIbeaR8GQu6okS qP2JseA0HKZLnaepv/qbxF0Rth24RyJTaatznHQHP1Qg8bi+KHDQg9l9G0MnIpxPlt0p ifC+f0j4OhgO1dOTlVl/UCuRacWKdneaS0bM9IARbvVuK4+38o/V8LWQPU7dHSEOaho6 8bMGwM5tnKPPP/0kgpqRRzo+mVH47AuAd0wd3NUxsgMibQa9ohHqYg3KEMRncdfl59+z kO7CBn2LPqG3s6CDq1qfaFAoxeaNR7mXwdBqdnp9SI0U2bD2o2ht9hwhjGNS6QZcZRSB +53Q== X-Gm-Message-State: AOAM530q9igWMPpqf3YpPPYMvqrdcqNl0qUvdv9u/abjjQ4Os8+TjJDN qPtXzgDC6yamOpaPOK8p03A= X-Received: by 2002:a37:9c82:: with SMTP id f124mr4221666qke.314.1606936269763; Wed, 02 Dec 2020 11:11:09 -0800 (PST) Received: from localhost ([2620:10d:c091:480::1:8dbd]) by smtp.gmail.com with ESMTPSA id b4sm1765150qtb.33.2020.12.02.11.11.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Dec 2020 11:11:09 -0800 (PST) Sender: Tejun Heo Date: Wed, 2 Dec 2020 14:10:41 -0500 From: Tejun Heo To: Yu Kuai Cc: axboe@kernel.dk, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, zhangxiaoxu5@huawei.com Subject: Re: [PATCH] blk-throttle: don't check whether or not lower limit is valid if CONFIG_BLK_DEV_THROTTLING_LOW is off Message-ID: References: <20201126031834.40807-1-yukuai3@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201126031834.40807-1-yukuai3@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 26, 2020 at 11:18:34AM +0800, Yu Kuai wrote: > blk_throtl_update_limit_valid() will search for descendants to see if > 'LIMIT_LOW' of bps/iops and READ/WRITE is nonzero. However, they're always > zero if CONFIG_BLK_DEV_THROTTLING_LOW is not set, furthermore, a lot of > time will be wasted to iterate descendants. > > Thus do nothing in blk_throtl_update_limit_valid() in such situation. > > Signed-off-by: Yu Kuai Acked-by: Tejun Heo Thanks. -- tejun