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 734E3EB64D9 for ; Thu, 6 Jul 2023 18:43:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231508AbjGFSnI (ORCPT ); Thu, 6 Jul 2023 14:43:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232495AbjGFSnG (ORCPT ); Thu, 6 Jul 2023 14:43:06 -0400 Received: from mail-pl1-f180.google.com (mail-pl1-f180.google.com [209.85.214.180]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 633491BF6; Thu, 6 Jul 2023 11:43:04 -0700 (PDT) Received: by mail-pl1-f180.google.com with SMTP id d9443c01a7336-1b852785a65so7451775ad.0; Thu, 06 Jul 2023 11:43:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688668984; x=1691260984; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=YJSqTuA4rxUcVPYnik9uob4hLh1/TwEOZHwAsiup89o=; b=CA/YQYucup3tOBIH5JozXwebx+BrsTBy3fBdruWBqJ1/NcbkQSlH8kGVMDewWXMD+V 4kXeuIYO8z2npwWnITOS5pwlVVEU/6plNqiuMOAmvG8APa2BC/DXe1QHH7a2yQD3DOWc 4jRxq0bQ0NIwixoA/35mzk+4S1GP+r3VI3hsxbQhhLE5x79tl1EraWjYeoz8R857Mxfx NbscO0OHYVv2G0FGokERxPrfvtQNl6ezjOOI5oYEg2Ka0lMck6uweKK0FgWGRCPxR7id 2pquPdP8ma//MP4H1N5jCk6CTU98AaUJnV2uUyY2UFARIvcWtu/0G7Je4i+h2qib11OY +89Q== X-Gm-Message-State: ABy/qLbuvXiqgTsktuHtFvpYU0gsy7O2+CJmoojngOU6fgonyimNYTym UFE2KDWwYgDoEZ9IMU/cuS0= X-Google-Smtp-Source: APBJJlHBYDfZfzJ5gmKtKg8N+6jJW7hn+N7mquB8h5rdgKOnD90vAzJCoOt8LhOYk0jlFL4f1L/Big== X-Received: by 2002:a17:903:32d1:b0:1b8:a67f:1c15 with SMTP id i17-20020a17090332d100b001b8a67f1c15mr9340335plr.25.1688668983758; Thu, 06 Jul 2023 11:43:03 -0700 (PDT) Received: from ?IPV6:2620:15c:211:201:a75c:9545:5328:a233? ([2620:15c:211:201:a75c:9545:5328:a233]) by smtp.gmail.com with ESMTPSA id 13-20020a170902c24d00b001b8a2edab6asm1737887plg.244.2023.07.06.11.43.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Jul 2023 11:43:03 -0700 (PDT) Message-ID: Date: Thu, 6 Jul 2023 11:43:01 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH RFC 0/7] blk-mq: improve tag fair sharing Content-Language: en-US To: Yu Kuai , axboe@kernel.dk Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, yi.zhang@huawei.com, yangerkun@huawei.com, Christoph Hellwig , "yukuai (C)" References: <20230618160738.54385-1-yukuai1@huaweicloud.com> <4c9fea33-9c30-4ab9-c210-95e09d323837@acm.org> <82d44ba1-4389-079c-935a-cbb49203ca27@huaweicloud.com> <84f9bfb4-293b-ad55-97e4-e8c611c5e9ca@huaweicloud.com> From: Bart Van Assche In-Reply-To: <84f9bfb4-293b-ad55-97e4-e8c611c5e9ca@huaweicloud.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 7/4/23 20:17, Yu Kuai wrote: > - currently borrowed tags will never be returned untill queue is idle, > I should figure out a way to return borrowed tags if this queue is not > busy, so that other queues can borrow tag from this queue. At least for UFS this is a significant disadvantage. If e.g. one SCSI command is sent to the UFS WLUN every 20 seconds and the request queue timeout is 30 seconds then borrowed tags will never be returned. The complexity of this patch series is a concern to me. The complexity of this patch series may be a barrier towards merging this patch series in the upstream kernel. Thanks, Bart.