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=-5.4 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 F0146C4338F for ; Wed, 4 Aug 2021 17:58:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CF51B61002 for ; Wed, 4 Aug 2021 17:58:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239985AbhHDR6S (ORCPT ); Wed, 4 Aug 2021 13:58:18 -0400 Received: from mail-pj1-f43.google.com ([209.85.216.43]:41898 "EHLO mail-pj1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238270AbhHDR6S (ORCPT ); Wed, 4 Aug 2021 13:58:18 -0400 Received: by mail-pj1-f43.google.com with SMTP id q17-20020a17090a2e11b02901757deaf2c8so4740630pjd.0 for ; Wed, 04 Aug 2021 10:58:05 -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=GIkQ3O0w6bhSupMgp4+vB9AZMw395lGEwUgPfZeNzx4=; b=P9+OL+Y19/s7vWTPK7lfwLQ57NlKsOzZ6d3JfC2nuYWQP/rJcPzEvzvHDcLDjdZKdx fvGiYsIN5JU6XmBfbVXSyUPBNZCdc1XtVJlzlDOdDBRkKnHR7IICY6eap6gVxrd74c6h SaIYkDYFtCUmsWMRlNT/9HaVPA288dlRF8QWEtVRBLov3RmgXx6HuizVOe0U5fgtKWat 9m9AnWbEUjqqhZNrD5DM/ftb+pxBeQ04uTaB3oGHN9sdjpPN8P/yyaGK/b9sIyQY2Kto 40iGXEWLIQyZRKLXHKJzBPkAuKp7mbRirVtlW+IWE7r1Ci1OiHBDXemjtG4ObjnwFVqd PfXQ== X-Gm-Message-State: AOAM531wVfj9Ms9gRoMHQ4NZGfsYpy2OAQqWBR1tYfxRAMdeIAhlGy2v oVp2Nr4q4txDUh/T1b3FR2E= X-Google-Smtp-Source: ABdhPJwZqzfJh4vbKeG+osIvAKTWEMCCrEIt4cf/OZQu1nZxbkRxOMv/CoInXdjNVnvBlrIT3gsNjA== X-Received: by 2002:a65:6554:: with SMTP id a20mr295335pgw.107.1628099884512; Wed, 04 Aug 2021 10:58:04 -0700 (PDT) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:1:8587:b3fe:5419:1ed7]) by smtp.gmail.com with ESMTPSA id 10sm3611221pjc.41.2021.08.04.10.58.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 Aug 2021 10:58:03 -0700 (PDT) Subject: Re: [PATCH v2 2/3] loop: Select I/O scheduler 'none' from inside add_disk() To: Christoph Hellwig Cc: Jens Axboe , linux-block@vger.kernel.org, Jaegeuk Kim , Ming Lei , Tetsuo Handa , Martijn Coenen References: <20210803182304.365053-1-bvanassche@acm.org> <20210803182304.365053-3-bvanassche@acm.org> <20210804053527.GA5711@lst.de> From: Bart Van Assche Message-ID: Date: Wed, 4 Aug 2021 10:58:01 -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: <20210804053527.GA5711@lst.de> 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 8/3/21 10:35 PM, Christoph Hellwig wrote: > On Tue, Aug 03, 2021 at 11:23:03AM -0700, Bart Van Assche wrote: >> We noticed that the user interface of Android devices becomes very slow >> under memory pressure. This is because Android uses the zram driver on top >> of the loop driver for swapping, > > Sorry, but that is just amazingly stupid. If you really want to swap > to compressed files introduce that support in the swap code instead of > coming up with dumb driver stacks from hell. Hi Christoph, That's an interesting suggestion. We can look into adding compression support in the swap code. Independent of the use case of this patch, is it acceptable to change the default I/O scheduler of loop devices from mq-deadline into none (patches 1 and 2 of this series)? Thanks, Bart.