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 1EBD7C3F6B0 for ; Fri, 19 Aug 2022 17:54:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350694AbiHSRyi (ORCPT ); Fri, 19 Aug 2022 13:54:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350171AbiHSRyK (ORCPT ); Fri, 19 Aug 2022 13:54:10 -0400 Received: from mail-pl1-x634.google.com (mail-pl1-x634.google.com [IPv6:2607:f8b0:4864:20::634]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 70D2D11A08; Fri, 19 Aug 2022 10:33:25 -0700 (PDT) Received: by mail-pl1-x634.google.com with SMTP id w14so4691850plp.9; Fri, 19 Aug 2022 10:33:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :from:to:cc; bh=fqadMmXWI3FPz7mWQ1shnlAoTXiP9jnMsgjYOJuOFoo=; b=XLoC5u3RQueoGHx7vAILKwaXo9QAjQrU4TwhNNPQBOd1CnzLc6TQpxCmCFhiADzo2M vVzngvi3WWgBQbHqiBk3ZDLCAUuPjsOGvq+AGpzzL5J1EfxslGp6P0d16cIryfiH4y/n xkTma1UrGwx13EnmFlj+t92DXI+pb/J7lFFi07Y6kiEK594GfromCsbC9ArT89I/NTo9 arjB8kANy2CdiyZSmvdv0vmifeMOLkJ7YYPu32SOgSPlcSb/X+g3dYWd/lAAaArmjvvn mSD19RWLbvEOBRRoOKBhYlBNuq2YnHIzJg8JAJEyfRCobB7OkDORfs/qQOxdqjBkUUAH mGKQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :x-gm-message-state:from:to:cc; bh=fqadMmXWI3FPz7mWQ1shnlAoTXiP9jnMsgjYOJuOFoo=; b=Us/QqrwaU8wtgIj5UZIzhCXKKTUbS/tRxWgL+qmDZR71NnWzqn1Ny0qrkrFPu14bil NfMRqIZvHub3+87Re3UHajn3l8OC39y4JgsJLoKDGoV4Cz3KiS5NhAH5HsrZsT+oXHaR ZdwdXtHXqUz4dKBZiuHy2QW8PMW+kffNrU2u7XWC8BKmL13SkW13YEe5aj6/2r8hQnVw FmXg5Ji4kpzFF3yGeMQ1uOEveSWMui3von3RAyQgjzy9txQqSiEMoF7GRrBrs8kNU8E9 t65RbRuWAfxiTXz02DUn7NrqmNW45ea/SjEeenCXBnhEQn4BVsXRlwW6vyMRQqAPgx3N ZNXA== X-Gm-Message-State: ACgBeo2+gLWUOPLK4S9abG7kQ2zkkwbR9/zGsAR1mCT7yd1QZOaQNQfx MtIXy50qembD1i9gjQ6cjl4= X-Google-Smtp-Source: AA6agR6oscwM7f9Y+IO+Kt+o2d0lLW6v3d+P4w7KCUmrGv6Fk8Oyu9zHo8XEtW7WcMdJO+Rj6oAyEA== X-Received: by 2002:a17:903:18a:b0:16f:9027:60dc with SMTP id z10-20020a170903018a00b0016f902760dcmr8243997plg.147.1660930404825; Fri, 19 Aug 2022 10:33:24 -0700 (PDT) Received: from localhost ([2620:10d:c090:400::5:db7d]) by smtp.gmail.com with ESMTPSA id s2-20020a170903200200b00172cb8b97a8sm279412pla.5.2022.08.19.10.33.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Aug 2022 10:33:24 -0700 (PDT) Sender: Tejun Heo Date: Fri, 19 Aug 2022 07:33:22 -1000 From: Tejun Heo To: Yu Kuai Cc: mkoutny@suse.com, axboe@kernel.dk, ming.lei@redhat.com, cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, "yukuai3@huawei.com >> yukuai (C)" Subject: Re: [PATCH v7 4/9] blk-throttle: fix io hung due to configuration updates Message-ID: References: <20220802140415.2960284-1-yukuai1@huaweicloud.com> <20220802140415.2960284-5-yukuai1@huaweicloud.com> <215b4842-c09f-d622-7127-c8b1d9ce3aa9@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hello, On Thu, Aug 18, 2022 at 09:16:28AM +0800, Yu Kuai wrote: > 在 2022/08/18 1:52, Tejun Heo 写道: > > On Wed, Aug 17, 2022 at 09:30:30AM +0800, Yu Kuai wrote: > > > > Would it be easier if the fields were signed? It's fragile and odd to > > > > explain "these are unsigned but if they underflow they behave just like > > > > signed when added" when they can just be signed. Also, I have a hard time > > > > understand what "preempt" means above. > > > > > > I think preempt shound never happen based on current FIFO > > > implementation, perhaps > > > > Can you elaborate what "preempt" is? > > Here preempt means that the bio that is throttled later somehow get > dispatched earlier, Michal thinks it's better to comment that the code > still works fine in this particular scenario. You'd have to spell it out. It's not clear "preempt" means the above. > > How about carryover_{ios|bytes}? > > Yes, that sounds good. > > By the way, should I use 'ios' here instead of 'io'? I was confused > because there are many places that is using 'io' currently. Yeah, blk-throttle.c is kinda inconsistent about that. It uses bytes/ios in some places and bytes/io in others. I'd prefer ios here. Thanks. -- tejun