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 50B44C3F6B0 for ; Wed, 17 Aug 2022 17:52:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230171AbiHQRwt (ORCPT ); Wed, 17 Aug 2022 13:52:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59908 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237632AbiHQRws (ORCPT ); Wed, 17 Aug 2022 13:52:48 -0400 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58F607DF4A; Wed, 17 Aug 2022 10:52:47 -0700 (PDT) Received: by mail-pj1-x1031.google.com with SMTP id o14-20020a17090a0a0e00b001fabfd3369cso1300238pjo.5; Wed, 17 Aug 2022 10:52:47 -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; bh=OSADlFbIj2e9HqyRVtp14PL1Xr6rNvJVCrKar0E+Zk8=; b=Zo40/TjPDHiWeNSjJknVi5F5cx4JHD2EGWguUAk4iAmlDsu/4A7LpbnUsr/85DnZrg cNVsm3cOlYXqTW8jVChsuOr7xhFKyi+9lk2ZNwU09JWHWHIb/oKc0DoVmlV0NZvYUHnm Qymufs9T4X3vDGdiuoeLG0Bo/vBqVPBJ607NDNvmv90r2CrohZAKj2yfXaB39sDXC7q4 YKNIfKMkeu/DQx5fq4gB+ou1zizz/7DxAYUADn+38nUmQvvl1SZx7VJCseh6RNsRoYY+ jr0SD74JXBFmuez17lcEPwJZTwYvN4rq++uouH/sBEsaA0sYYyZ7xD7gAIhOAm89OD7w hoYw== 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; bh=OSADlFbIj2e9HqyRVtp14PL1Xr6rNvJVCrKar0E+Zk8=; b=bO2tjmVbyg4KIhxCKjwoEN0P1JHISLmiwfLQMqSH0yK2ThJBuZT45p4RoW67Vqaw9b OAS9ALkwajGVMYD7jSZjC5f/4Cmh6MoqieXK8+zYgbUZFqNn3axxIjAqFswTpoCbrfTS DQlC4nDuly0b1ibkt94egqlmZtzu6CPqi3CW53abuI3X+Dsr17jL08kxQ7kx8D7rOatz ZpZMYgRF8nGySaPJgehERhIwDqLmmij/BP0EuJoGnYBRQhM+rCTxNeh1E446IXOzXIbb L2ESlLkD8MjFIYGkBGKCz33LMKGJ7I//aXp0u4aqbWLCkX154Zh9RrCBsKyrtZxaWr4C qAGg== X-Gm-Message-State: ACgBeo35QY0FVcKxCJUnaTb3NxP9Bv8u3dwGpiuCFQtpb5ZjMHG9oSFi kMrzKOfVUylnGSFHhrD0+Lg= X-Google-Smtp-Source: AA6agR6o7+VXireczEoNvcJf5BC9qxlMA/b1TDhfVukLZvA2R+1sU4T83EW4L6XIWp8y2ygsndmwEA== X-Received: by 2002:a17:90b:38c9:b0:1f7:28bb:aa16 with SMTP id nn9-20020a17090b38c900b001f728bbaa16mr4832078pjb.201.1660758766791; Wed, 17 Aug 2022 10:52:46 -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 a8-20020aa79708000000b0052e6c058bccsm10695677pfg.61.2022.08.17.10.52.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Aug 2022 10:52:46 -0700 (PDT) Sender: Tejun Heo Date: Wed, 17 Aug 2022 07:52:45 -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, "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=us-ascii Content-Disposition: inline In-Reply-To: <215b4842-c09f-d622-7127-c8b1d9ce3aa9@huaweicloud.com> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org 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? > > > + if (bps_limit != U64_MAX) > > > + tg->bytes_skipped[rw] += > > > + calculate_bytes_allowed(bps_limit, jiffy_elapsed) - > > > + tg->bytes_disp[rw]; > > > + if (iops_limit != UINT_MAX) > > > + tg->io_skipped[rw] += > > > + calculate_io_allowed(iops_limit, jiffy_elapsed) - > > > + tg->io_disp[rw]; > > > > So, this is calculating the budgets to carry over. Can we name them > > accordingly? I don't know what "skipped" means. > > Yeah, thanks for you advice, art of naming is a little hard for me... > How do you think about these name: extended_bytes/io_budget? How about carryover_{ios|bytes}? Thanks. -- tejun