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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE511C432BE for ; Fri, 13 Aug 2021 17:17:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B5B5F60F51 for ; Fri, 13 Aug 2021 17:17:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232179AbhHMRSN (ORCPT ); Fri, 13 Aug 2021 13:18:13 -0400 Received: from mail-pl1-f178.google.com ([209.85.214.178]:34329 "EHLO mail-pl1-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230316AbhHMRSM (ORCPT ); Fri, 13 Aug 2021 13:18:12 -0400 Received: by mail-pl1-f178.google.com with SMTP id d1so12889158pll.1 for ; Fri, 13 Aug 2021 10:17:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=6ienZbwguL6JxIZLyDC7vEnqfM94gw/FEoQHX2SJ1HE=; b=YuBB5fCM5pHZww+UEiPRUZ887IXmYpI0tKsEfbJvKc4B6YxX/APymeMBCEicNRErzT oco0+s8NTRyiJG+Z/UvsUiCuucKaKRBC8vLCGu1rWzJ9jQ2bpb6dCvDrHdBcUxtGRz1G DUB5ZLpqF7PDlfXGWA0GnCRI7PNe+gFauNr3K5g/wazJtWXcxwFvmobLoM9E89+Uc7ZY IbBrpTK16NP502RwiPXpGO8NAR1q92XyJNCIdS0ddDDjyYeeSO20wb9RiqbxCb++eukW PF6Rna2YK6mmgmvWiJqP393ro2NppkAhEXbCDxdfKgnsi3w3D0y+4//fDQ3Q1gWPerhC 8aww== X-Gm-Message-State: AOAM530ICa4IOwjXmSLHLw5S7wNJPN3OOLPGaGcoH5MGoParnGhl7sdL 00tpsgynh48WXvQ2MCziZZIW5wWsUSaqhgfq X-Google-Smtp-Source: ABdhPJwm3IIQ3W31mWTa9g2O+2CTZyp/xzI1hC3pUVTsgG5I8g0vUvTfAj1kh/6t+F5CYBA9GbZJWg== X-Received: by 2002:a17:90a:d509:: with SMTP id t9mr3508010pju.225.1628875064503; Fri, 13 Aug 2021 10:17:44 -0700 (PDT) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:1:b745:b195:ae3f:f02d]) by smtp.gmail.com with ESMTPSA id j2sm2948519pfe.201.2021.08.13.10.17.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 13 Aug 2021 10:17:43 -0700 (PDT) Subject: Re: [PATCH block-5.14] Revert "block/mq-deadline: Add cgroup support" To: Tejun Heo , Damien Le Moal Cc: Jens Axboe , "linux-block@vger.kernel.org" References: <035f8334-3b69-667d-be91-92dcab9dc887@acm.org> <00e13a7b-6009-a9d7-41ba-aae82f5813de@acm.org> <631e7e18-52ca-9bec-0150-bac755e0ff24@acm.org> From: Bart Van Assche Message-ID: <5527319b-ba0c-00a3-19cf-612f2e2b073d@acm.org> Date: Fri, 13 Aug 2021 10:17:42 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 8/13/21 9:29 AM, Tejun Heo wrote: > The problem with complex optional hardware features is often the > accompanying variability in terms of availability, reliability and > behavior. The track record has been pretty sad. That isn't to say this > won't be useful for anybody but it'd need careful coordination in > terms of picking hardware vendor and model and ensuring vendor > support, which kinda severely limits the usefulness. I think the above view is too negative. Companies that store large amounts of data have the power to make this happen by only buying storage devices that support I/O prioritization well enough. Bart.